|ATP World Tour Finals, O2 Arena London, 9-16 November|
|Coverage: Afternoon sessions (14:00 GMT) and first semi-final (14:00 GMT) on BBC Two & BBC website, final on BBC Three & BBC website (19:00 GMT); live commentary of each match on 5 live sports extra, live text commentary on BBC website|
Kei Nishikori fought back to beat David Ferrer and put the pressure on Andy Murray at the ATP World Tour Finals.
Japan's Nishikori saw off Ferrer - a late replacement for the injured Milos Raonic - 4-6 6-4 6-1 in Group B.
The result means Roger Federer is through to the semi-finals ahead of his final round-robin match against Murray at 20:00 GMT.
Murray must beat the six-time champion in straight sets to qualify, and with it top the group.
Failure to do so will see the Swiss qualify first and Nishikori second, with the group winner likely to avoid world number one Novak Djokovic in the semis.
Nishikori, 24, played his part with 41 winners in an impressive win over Ferrer, the first three-set match of the week at the O2 Arena.
Ferrer, 33, might have only come to London as an alternate but he had been seen practising hard every day and, well-rested since his last competitive match, arguably offered a trickier opponent than the struggling Raonic.
"The third set was almost perfect," said Nishikori. "I served well and everything worked well. We've played each other four times this year and always three sets.
"It was really difficult to make this adjustment - they told me one hour before the match, it was tough to change tactics but I'd prepared well and I'm happy to win today."
Asked if he would watch the late match to learn his fate, Nishikori added: "I don't think so. I'm just going to wait for the result because I want to eat a good dinner today."
The match followed the pattern of their previous three meetings in 2014, with Nishikori's greater power helping him past the Spaniard in three sets.
The Japanese player, making his debut at the season finale, reproduced the kind of form that saw him beat Murray on the opening day.
|Former British number one Tim Henman, commentating on BBC Two:|
|"I think it's fitting that Nishikori went through. Ferrer came in as a reserve and put in a great performance. He can't have had much notice, but the way these guys move, it was really nip and tuck in first two sets. When Nishikori serves consistently he can dictate the points from the back of the court."|
He had already conjured an outrageous cross-court drop shot and a thumping forehand winner before breaking serve in game seven, and it came as a surprise when his level suddenly dropped.
Two errors gifted Ferrer a chance to hit straight back and he did so in a punishing rally, before grabbing the set two games later when Nishikori netted a smash.
A straight-sets defeat would have further dented Nishikori's hopes of qualifying for the last four, and the US Open finalist made sure he avoided that fate in convincing style.
A break at the start of the second was enough to ultimately give him the set, a backhand winner whistling past Ferrer on set point, and the world number five was at his very best as he reeled off five games in a row.
A killer drop shot was just one of 15 winners in the final set alone and, after the battling Ferrer had seen four break points slip by at 4-0 down, Nishikori wrapped up his second win of the week after one hour and 56 minutes.
"Kei, he's playing very good," said Ferrer, who arrived in London on Sunday. "He's playing with confidence with his game. In the third set, I was a little bit tight, and he was better."