LONDON -- There had been a chance the 'Big Four' were going to fill out Saturday's semifinals at the O2 Arena -- until Stan Wawrinka spoiled the party, that is.
The Swiss seems to have got the hang of these World Tour Finals. For the third successive year, he has inserted himself into the semifinal picture, this time at the expense of Andy Murray.
Wawrinka won a tight first-set on a tie-break before going up a double break in the second set. Murray managed to keep his hopes alive by clawing one break back at 5-2 down, and held a further two break points at 5-4, but Wawrinka held his nerve to close out a 7-6(4), 6-4 win and break British hearts.
Another last-four meeting with Roger Federer in London now awaits Wawrinka, who lost an epic three-setter to his compatriot after failing to take four match points in 2014.
"[Federer's] playing really well," Wawrinka said in his post-match press conference. "It's tough to play indoor, especially World Tour Final, he is always fit, always ready.
"Last year was an opportunity to beat him, didn't take them. Let's see, I had a tough match now, two hours match with a lot of pressure. I also feel quite tired. I'm going to be focused on that, try to rest, try to recover and be ready for hopefully a good match."
Wawrinka also admitted the dynamic between himself and Federer has altered since he became a grand slam champion at the 2014 Australian Open.
"Well, yeah, it changed," he added. "But [it's] like [that] with all the players. It changes because we start to talk about different things. We also start to know each other better and better, with last year playing Davis Cup, sharing a lot of good memories together. Always been there. I practice so many times with him. He's amazing for the game, that's for sure. But he's always been really good with me. I always enjoy to share the court with him."
Earlier on Friday, Rafael Nadal came from a set down to win a gruelling match against his fellow Spaniard David Ferrer 6-7(2), 6-3, 6-4 in a battle which lasted over two and a half hours.
It may have been a far cry from his swashbuckling wins against Wawrinka and Murray earlier in the week, but former world No.1 Nadal gave his confidence another timely top-up by sweeping his group going into Saturday's semifinal against Novak Djokovic.
Next comes chapter 46 of their intense rivalry, with Nadal a whisker in front at 23-22. But Djokovic has won all three matches this year, including the Beijing final in straight sets last month.
"That's another step. A really difficult match against a player who is playing just better, impossible I believe," Nadal said in his press conference. "I need to play my best to have any chance. That's what I going to try.
"But the right work is done. Lot of positive things during the last weeks. Very good confirmation this week. So tomorrow is another opportunity to compete against the best, to see if I am able to compete at a very high level again."
It has been a season largely plagued by self-doubts for Nadal, having fallen to No.10 in June for the first time since 2005 and suffered the most losses (19) in a single campaign in his 14-year career.
But he is finishing it by suggesting he is returning to top form. Nadal now has 17-4 record following the US Open, including another final in Basel and a semifinal in Shanghai.
"For me the main thing is keep going the same way, keep practicing the same way, the same things I am doing to try to start next year with that energy that I have today," said Nadal. "If I am able to keep playing like this, I think next year can be a positive year for me.
He added: "Against Novak, I know what I have to do. But be very difficult to make it. Is a big challenge. But I am not worried about it. I am happy about the things, how are going.
"I cannot go crazy. I cannot go on the court and thinking that I have to do something that I cannot do it. I going to try to play my game. I going to try to play aggressive. I going to try to be strong mentally."