Three of the semifinalists have been defined in South America's Copa Libertadores with River Plate and Brazilian powerhouses Palmeiras and Santos punching their tickets.
But if Boca Juniors are able to overturn Racing's 1-0 first leg lead and set up a final four of two Buenos Aires clubs and two Sao Paulo state sides, then three powerful storylines will still be alive.
- Stream ESPN FC Daily on ESPN+ (U.S. only)
- ESPN+ viewer's guide: Bundesliga, Serie A, MLS, FA Cup and more
One is Boca's dream of gaining revenge for the defeat suffered in 2018 in the final at the hands of their historic rivals River Plate. Boca not only want to reach the final on January 30th at the Maracana, they want to play River there -- should both advance -- and hand out payback for losing to Los Millionarios in Madrid in one of the tournament's most memorable editions.
The second storyline is the desire to win the title to pay tribute to the memory of the late Diego Maradona. It is because of Maradona's passing that Boca's schedule is a week behind everyone else. They were due to take the field against Brazil's Internacional on the day he died. That game was put back seven days and, initially, everything went to plan. They were utterly dominant should have won by more than the 1-0 margin. Carlos Tevez, the current idol and a great friend of Maradona, scored the goal and celebrated in appropriate style, removing his shirt to reveal an old No. 10 Boca top that used to belong to Maradona.
Subsequent events, though, would appear to point to a worrying conclusion. Boca's performance that night may have less to do with their own merits, and more to do with a disastrous starting line up chosen by Abel Braga, Inter's recently appointed coach. A week later in Buenos Aires Inter were much changed and greatly improved. This time Boca were fortunate to come away with a 1-0 defeat, and seal their place in the quarterfinals after a penalty shoot-out.
And then, a week ago, Boca were similarly poor in their 1-0 defeat across town against Racing. They have barely looked like scoring in the last two games, and have lost consecutive matches in the competition for the first time since the 2016 semifinals.
But if Boca can come from behind to qualify in their famous Bombonera stadium, then it sets up a mighty third storyline for the semifinal -- the Boca Juniors of Diego Maradona against the Santos of Pele.
Now they must win -- which means that it is decision time for Miguel Angel Russo, who was also in charge when Boca won the title for the last time back in 2007. Much of Russo's success this year has rested on the way that he has dealt with the veteran Tevez, who looked a busted flush last year under previous coach Gustavo Alfaro. Russo has galvanised and rejuvenated the 36-year-old by making him feel important.
So how does he get the best out of Tevez on Wednesday? He could play him up front, just as he did in the first leg, with the talented but wayward Colombian Edwin Cardona operating just behind him. Or he could bring in the hard working but limited centre forward Franco Soldano -- who scored his first goal in 16 games at the weekend -- to take some of the strain off Tevez.
The bold choice there would be to use Cardona in a deeper midfield role, though it might leave his team dangerously open. Boca should be wary of over-committing to attack. Under dynamic young Sebastian Beccacece, Racing will be keen to grab a vital away goal. And although veteran centre-forward Lisando Lopez has not found the target since October of last year, he has the nous to tie up the Boca defenders and slip a pass to his attacking colleagues.
The Paraguayan Lorenzo Melgarejo is especially dangerous, and celebrated his return from injury with the only goal of last week's match. With his three centre back formation, Beccacece will seek to push up and defend far from goal, and also defend with the ball when possible, using his wing backs to gain width high up the field. Boca's task, then, is not easy. Racing have conceded just 6 goals in the 9 games they have played, have yet to concede more than one per match and held on well under pressure in the previous round away to reigning champions Flamengo.
The campaign of Santos, who last won the competition in 2010 behind an emerging Neymar, is an extraordinary story in its own right. The club have battled through financial problems deep enough to see the club president impeached and punishments from FIFA. They have suffered a coronavirus outbreak, including the loss of one of star winger Yeferson Soteldo, on the eve of the quarterfinals. Key centre-back Lucas Verissimo wants to leave and has had to be coaxed into playing.
O Peixe fought their way through to the quarterfinals with a series of tough, single goal victories. And then they came up against compatriots Gremio in cracking form and justifiably confident of making it to a fourth consecutive Libertadores semifinal. After a 1-1 draw with a team of youngsters Santos stormed the last four with a memorable 4-1 win in the second leg -- the only time in this year's competition they have won a match by a margin greater than one goal.
Whatever happens in January, Santos have had a Copa Libertadores run to remember. But the semifinal will be even more memorable if Boca is there to greet them and set up a clash of the team of O Rei against the club of El Diez.