Federer not in the mood for clowning around against Djokovic

Heading into this Barclays ATP World Tour Finals, only one man had managed to take as many as two matches from world No. 1 Novak Djokovic in this, his finest season.

And now, Roger Federer -- looking remarkably spry at the age of 34 -- has three wins against Djokovic after Tuesday evening's 7-5, 6-2 in round robin play at the year-end championships.

The defeat abruptly ended a 23-match winning streak in 2015 and a 15-0 run at the ATP Finals. It was over in 77 minutes -- but it felt faster.

Afterward, Federer sounded a little miffed when told that Djokovic said to reporters he felt he handed the win to Federer.

"He handed the win?" Federer asked.

Yes, Federer was told.

"Well, he wasn't as good as in the first set," Federer said. "But I feel, honestly, with the way he's played this season, you still have to put him away. It's not an easy thing to do. It's not like he played terrible. I know he can play better.

"Why did he play that way? I'd like to give myself credit for that, quite honestly, yeah."

The No. 3-seeded Federer, thus, managed to (barely) continue his career head-to-head mastery over Djokovic, 22-21, at the O2 Arena in London. Federer has never trailed in the compelling series.

Afterward, without giving any specifics, Djokovic said he was feeling less than his best.

"He tactically played well," Djokovic said of Federer. "Undoubtedly, he was the better player on the court. But I think I also allowed him to play and penetrate through the ball and dictate the tempo from the baseline.

"I didn't have this follow-through on my shots, no depth, honestly, many mistakes. Basically, if you play this way against Roger, you have no chance."

Indeed, it was a surprisingly comfortable victory for Federer, who is 2-0 in Group Stan Smith play and has now advanced to the semifinals of this event for the 13th time in 14 years. He has an inconsequential match remaining against Kei Nishikori.

Federer served far more effectively than Djokovic, winning 75 percent of his first-service points, compared to 51 percent for the 28-year-old Serb.

Federer actually broke Djokovic and built a 2-0 second-set lead but immediately gave back the break. With Djokovic serving at 2-3, Federer ripped a backhand pass up the line that clipped the tape and dropped in.

Djokovic managed to win only two of three break-point opportunities, while Federer was a lusty 4-for-8.

Federer lost back-to-back Grand Slam singles finals to Djokovic, at Wimbledon and the US Open, but now finds himself 3-4, with a potential chance to level that mark in the finals.

Here's what else went down on Day 3 at the year-end championships:

Nishikori catches a break

In the only singles match of the tournament so far to go the maximum distance, No. 8 seed Nishikori handled No. 6 Tomas Berdych 7-5, 3-6, 6-3.

Berdych, now 0-2 in round robin play, is almost certainly done.

This was an entertaining match and it was deadlocked at 3-all in the third when Nishikori got the break he needed -- but it wasn't a service break.

With Nishikori serving, Berdych took control of the point, pulling the Japanese player way off the court on the ad side. But Nishikori, sprinting, tracked down a desperate, lunging backhand to keep the point alive. A few swings later, Berdych drove a backhand into the net to return the score to deuce.

"That was a really big point," Nishikori said in his postmatch interview. "He had three, four shots that he went really aggressive. I was defense all the time. I mean, last shot I kind of went for it, closed my eyes. Was a little bit lucky I made that shot.

"But, yeah, after that, I start playing better."

As Nishikori prepared to serve the next point, he peered at his racket strings. He looked surprised. He raised a hand toward Berdych and then went to his chair and switched rackets. A television close-up revealed that the retired racket had a big crack clear through the frame on one side of the string bed. Replays suggested it was sustained when Nishikori had leaned on the frame to keep his balance and change direction when he made the save during that critical break point.

When play resumed, Nishiori held and broke Berdych with ease as he won 11 of the last 12 points of the match.

Eight is (more than) enough

Break up the doubles team of Rohan Bopanna and Florin Mergea.

Coming off an opening victory against the No. 1-ranked Bryan brothers, the No. 8 seeds kept it going with a 6-3, 7-6 (5) victory over the No. 4-seeded Jamie Murray and John Peers. That makes them 2-0 and the leading team in Group Ashe/Smith.

Meanwhile, Bob and Mike Bryan won a critical match, 6-3, 6-2, over the No. 5-seeded team of Simone Bolelli and Fabio Fognini. The Bryans will play Murray-Peers on Thursday, with the winner likely advancing to the semifinals.

On tap Wednesday

There's another blockbuster on the schedule Wednesday: No. 2 Andy Murray versus No. 5 Rafael Nadal (9 a.m. ET on ESPN3).

Nadal holds a 15-6 career head-to-head edge, but Murray won their only previous match this year, 6-3, 6-2 in the finals at Madrid.

With a win, Murray can lock down the No. 2 year-end ranking, his highest finish ever.

In the late match, Stan Wawrinka takes on David Ferrer, both of whom lost their opener (3 p.m. ET on ESPN3).