How Fernando Alonso kept Sergio Perez's faster Red Bull at bay in Brazil

The battle between Fernando Alonso and Sergio Perez at the Sao Paulo Grand Prix was modern Formula One racing at its finest. Two drivers determined to return to the podium for the first time in over five races, but two drivers who were equally set on doing it fairly.

At no stage did one driver force the other off the track and at no stage were track limits exceeded in trying to gain an advantage. This was pure racing -- at times in excess of 200 mph -- and a showcase for why Interlagos remains one of the best racing circuits in Formula One.

The build up

As with any battle for position in the final two laps of a grand prix, an awful lot happened before the two cars went wheel to wheel. Alonso's race had initially got off to a poor start when he lost positions to Lando Norris and Lewis Hamilton on the run down to Turn 1, but a red flag for an accident further down the field gave him another shot at a standing start from fourth on the grid and he grasped it.

Hamilton attempted to pass Norris into Turn 1 for second place at the restart but locked up, allowing Alonso to get a better run through the Senna 'S' and complete a move on the inside at Turn 4 to take third position. For Alonso, this decisive action at the restart was key to his podium finish.

"To be honest, the most important overtaking of the race has been Hamilton into Turn 4 on lap one," Alonso said after the chequered flag. "That changed my race.

"If I start P4 and I have to fight with Hamilton in the first stint even if I can eventually get him from lap 10 or whatever, my tyres will never be in a condition to extend the first stint and then have a tyre advantage to Checo in the second stint and third stint, so for me there is one crucial moment of my race and it's lap one, into Turn 4 with Hamilton."

It's a factor that wasn't lost on Perez either. On paper the Red Bull is a superior car to the Aston Martin -- demonstrated by Max Verstappen winning the race a further 34 seconds up the road -- but Perez was stuck behind Alonso for nearly half the race.

Perez had lined up seventh on the grid for the red flag restart and only made up one position on the opening lap when he passed Alonso's teammate Lance Stroll into Turn 1. He then experienced what Alonso had feared, getting stuck behind the Mercedes of George Russell for ten laps and then Hamilton for another four.

Arguably a bigger setback came when Red Bull reacted to Mercedes' decision to pit its cars early. Hamilton pitted on lap 18 after excessive tyre degradation on the soft compound, followed by Russell on lap 19 and Perez on lap 20. In pitting two laps later than Hamilton, Perez came out behind the Mercedes and had to repass him on track, but it had a much bigger impact on his race as it also meant he pitted six laps earlier than Alonso.

That gave Alonso the advantage of fresher tyres for the entire second stint of the race, something that prevented Red Bull from making the most of its better car performance at the final round of pit stops. Midway through the second stint Perez found himself just over a second behind the Aston Martin, but when it came to the crucial few laps before the next set of pit stops, Alonso extended his lead to 3.8s to stop Perez pitting earlier and undercutting him.

From that point onwards, Red Bull's strategic options were exhausted, leaving Perez to do the hard work on the track.

"We shouldn't have followed Lewis in on the first stint," Perez said on team radio as he returned to the pits after the chequered flag, pointing to the fact that the timing of his first pit stop hurt him in the battle that would later unfold with Alonso.

A defensive masterclass

Perez made his second pit stop on lap 46 and Alonso his on lap 47, setting up a straight fight on soft tyres to the end of the race. By lap 52 of 71 Perez was already on Alonso's tail and it was at this point that Alonso made his last radio communication from car to pit wall until the chequered flag.

"Give me the gap [to Perez] and that's it," he said to his race engineer in a plea to eliminate any unnecessary distractions.

With Perez drawing within DRS range, Alonso knew his third place was at risk and it's at this point that he started to adpat his approach to two key corners.

Through Turns 10 and 12, the two-time world champion no longer took the conventional racing line of least resistance: wide on entry, hitting the apex and wide on exit. Instead, he took what is known as the 'V line', going deep into the corner, missing the apex but rotating the car quickly to allow him to straighten it up sooner, pick up the throttle earlier and carry more speed out of the corner.

This technique meant his minimum speed in the corner was slower than Perez, something that would be undesirable on a qualifying lap but a necessary sacrifice to defend position in the race. It almost looked clumsy on TV as Perez got tantalisingly close to the Aston Martin on the apex of the corners on each lap, only for Alonso to extend his gap as he accelerated away.

By taking his 'V line' in the slow Turn 10, named Bico de Pato (Portuguese for Duck's Bill and a colloquial term for a hairpin in Brazil), Alonso ensured Perez wouldn't be close enough to him through the high-speed Turn 11 to try a lunge into Turn 12, named Juncao (Junction in English). That in turn allowed him the freedom to 'V' Juncao, running wide of the apex, rotating the car quickly and picking up the throttle early again to carry as much speed as possible up the long hill to the pit straight.

This was where the pay-off mattered most as Perez's best chance to pass the Aston Martin was always going to be with DRS in to Turn 1 or by forcing Alonso to defend in Turn 1 so that he was off the racing line through the Senna 'S' and unable to defend when Perez gained DRS again ahead of Turn 4.

Perez adapts

The first sign of a crack in Alonso's defence came on lap 60, when, still sticking to his unorthodox lines in Turns 10 and 12, Perez nailed his more conventional approach to Juncao and got within 0.5s of the Aston Martin on the exit of the corner. Both drivers were told by their engineers to use as much electrical boost from their engine's hybrid systems as possible but Perez had the added advantage of DRS.

Alonso recognised the threat early and moved to block the inside line as they approached the braking zone for Turn 1. That had the potential to compromise his run through the Senna 'S' and leave him vulnerable at Turn 4, but Alonso was slower than normal through the apex of Turn 1, blocking Perez's chance to pick up the throttle earlier and maximising his own exit through Turns 2 and 3. Perez had a look at a move into Turn 4 but wasn't close enough to make it stick.

Perez then spent the next few laps struggling to get close to Alonso and complaining that the Aston Martin, which was running a smaller rear wing that provided less drag than the Red Bull's, was "really fast down the main straight". With frustration building in the Red Bull cockpit, Perez's race engineer, Hugh Bird, suggested his driver mimic Alonso's tactics in Turns 10 and 12.

"Try a bit wider on the exit of Turn 12 for traction," Bird said on lap 64. "Get that exit."

Later round the lap, Bird added: "Follow Fernando's line in Turn 10 and Turn 12."

Perez's attempt to 'V' Turn 10 on lap 64 was hampered by his lack of front downforce in the turbulent air from Alonso's car, meaning he struggled to get the car rotated in the same way Alonso could.

"No, if I follow his line, I pick up [the throttle] too late," Perez said over team radio at the start of lap 65.

"Focus on the exit of 12, give up [speed] on entry and focus on the exit," Bird replied.

Perez then attempted a wider line through both corners but ended up even further off Alonso on the pit straight and nowhere near him as they approached Turn 1.

"I think when you run just in front of another car, you have better downforce, you have clean air and that was maybe good for maintenance of tyre management," Alonso said after the race. "And he [Perez] was struggling a little bit to go into Turns 10, 11 and 12 behind another car.

"That was probably the game that we were playing. Those three corners were crucial for the overtaking opportunity. And yeah, when you are the car in front, you have better grip, always."

What's more, Alonso occasionally mixed things up, opting to take a conventional line to Turn 10 on lap 68 and again on lap 69 after several laps of running the wider line.

"I was using the energy [from the hybrid system] also in the straights just to make sure that there was no opportunity for Checo," Alonso explained. "And yeah, in the lines, we were just changing lines sometimes. I didn't want to be always on the same line, if possible, like this.

"If he goes on the inside, I was from time to time on the inside from time to time on the outside. So it was not a clear direction for him to really change the racing line and take the opportunity for some clean air. So I was just trying to get some turbulence to his front nose."

A fight to remember

Just as it looked like all hope was lost for Perez, he made the wide line work through Turn 10 on lap 69 and then nailed the apex of Turn 12 to get good traction on the hill up towards the pit straight.

It was clear from the gap between the cars as they exited that the corner that this would be Perez's big chance, and with the help of DRS and deployment of his battery power he forced a gap on the inside of Turn 1 at the start of lap 70 and passed Alonso.

"For 30 laps I had the pressure from Checo, but yeah, when he passed me, two laps to the end, I thought OK, going on the podium is not possible anymore," Alonso admitted after the race.

The Aston Martin driver attempted to retake the position into Turn 4 on the penultimate lap but Perez successfully blocked him by parking his car in the middle of the road under braking. Alonso got a better run through the corner as a result but had to lift fully off the throttle in Turn 5 to avoid losing his front wing against the left rear wheel of the Red Bull.

As the pursuer, Alonso returned to conventional racing lines through Turns 10 and 12 and discovered just how tough it was to follow another car as he slid wide through the exit of Juncao, potentially ruining his last chance of passing the Red Bull into Turn 1 at the top of the hill.

But Perez, now finally ahead of Alonso, appeared overcautious on the entry to Turn 1 and hit the brakes late while taking an unnecessarily defensive line on the inside of the corner. That put Perez off line through the Senna 'S' and opened up a chance for Alonso to pass at Turn 4 on the final lap.

"He braked a little bit late in to Turn 1 and I thought, 'OK, I go for it into 4'," Alonso said after the race.

The move looked spectacular as Perez blocked the inside, forcing Alonso to jink to the outside before the braking zone and swoop back across in front of the Red Bull in Turn 4 to take the position. Advantage Alonso once more, but both drivers knew it would all come down to Turns 10, 11 and 12 to decide who won one final drag race up the hill to the chequered flag.

Much like lap 69 when Perez set up his successful pass at Turn 1 on lap 70, Alonso took a conventional line in Turn 10 as Perez went to the outside and got the better exit to remain tucked under the Aston Martin's rear wing through Turn 11. In Turn 12, the roles reversed with Alonso taking the wide line as Perez ducked underneath on the conventional line.

Both fired out of the final corner and up the hill at full throttle while being told to deplete all the power left in their batteries to boost the power of their screaming V6 engines. Interestingly, Perez had to be told twice to "press and hold" his electrical boost button by his engineer, which may mean he wasn't using it as early as he should have been or could just have been Bird reaffirming the message.

Perez's closing speed was huge, and as the two cars hurtled towards the chequered flag he used his DRS advantage to slingshot around the outside of Alonso. To the naked eye, it was too close to call but a photo finish confirmed Alonso held the position by 0.053s as they crossed the line.

After six races without a podium, Alonso sounded elated over team radio.

"This is for you guys!" he said to his team. "This is for you - all of you guys, all the factory, everyone. Everyone, this is for you! Thank you very much."

Although he missed out on what should have been his first podium since the Italian Grand Prix in early September, Perez was magnanimous in defeat.

"I have to say well done to Fernando, because it was great fight. Very fair racing," Perez added after the race. "And that's really good, because how hard we race each other with always a lot of room, I think with very few drivers you can do this on the grid.

"You know that Fernando will always try to play any game, but he will always be fair. It was great racing. I think whoever got the podium was well deserved, and he got it."

Aside from the two drivers there was one other star of Sunday afternoon's battle for the final podium position. For several years now, Interlagos has offered up some of the most thrilling races of the F1 season and the 20-lap battle between Alonso and Perez stands as a case study as to why it is among the best circuits on the schedule.

"When there is an overtake done into Turn 1, there is a possibility -- a strong possibility -- that into Turn 4 someone will get the position back," Alonso said on Sunday evening. "So that's why we see some very nice battles in races always in Interlagos.

"It has been a spectacular weekend, as always here in Brazil. Sometimes it's the weather providing this great show and I think this weekend without any rain or any weather we saw incredible races. So there is something in this track that always give a perfect opportunity for Formula One to shine."