Djokovic has already been handed the ATP’s No. 1 player trophy for 2015, but judging from his even-more-efficient-than-normal dismantling of Nishikori on Sunday, the Serb isn’t taking his foot off the gas or taking this tournament lightly. What does he have to gain by winning his fourth WTF title in a row? I’d say Djokovic wants to (a) finish his best season the way it should be finished, with a title; and (b) go into the new year looking and feeling invulnerable, and with as much momentum as possible. Right now, winning must feel like a spell that he's under, and that he never wants to break. There’s no reason to think he will this week.
*2015 record: 59-10
Record vs. group: 48-29*
Speaking of momentum, here’s a chance for Federer to grab a little heading into 2016. The last time he reached No. 1, in 2012, he used a victory at this event the previous November to help propel him upward. The six-time WTF champion hasn’t won it since, and last year he didn't play the final against Djokovic because of a bad back and a looming Davis Cup final the following weekend. This time, after an early exit from Paris, Federer should be rested, and he should be happy to have a chance to take two cracks at Djokovic before the year is done.
*2015 Record: 57-19
Record vs. group: 9-37*
It’s been a long season for the 30-year-old. A coaching change gave him a boost, and a trip to the Australian Open semifinals, to start. But while Berdych would go on to win two titles, he would also lose in the round of 16 at the last three majors—age, ever so slowly, has been catching up to him. For now, he remains in his usual position, just outside the Top 5, and looking at an uphill climb in London. In his five previous trips to the event, he has reached the semifinals just once. Berdych gave Djokovic a two-tiebreaker run last week in Paris, but his 9-37 head-to-head against his fellow group members—he even has a losing record to Nishikori—speaks for itself.
*2015 Record: 53-14
Record vs. group: 7-9*
Nishikori retired last week in Paris with a back injury, the latest in an innumerable series of physical issues, and he was hardly in top form against Djokovic on Sunday. We’ll see what he has left this week, but a quick exit would feel like a step back. Last year he reached the semifinals in London; this season, despite winning three mid-level events, he hasn’t been at his best when it has mattered most.