Andy Murray aims for ATP World Tour Finals last four against Kei Nishikori
|ATP World Tour Finals - Andy Murray v Kei Nishikori|
|Venue: O2 Arena, London Date: Wednesday 16 November Time: 14:00 GMT|
|Coverage: Live coverage on BBC Two, BBC Radio 5 live sports extra & BBC Sport website, tablets, mobiles and app. Click here for details.|
Andy Murray will try to reach the ATP World Tour Finals semi-finals for the first time in four years when he takes on Japan's Kei Nishikori on Wednesday.
The pair meet in the John McEnroe Group at 14:00 GMT, live on BBC Two, online and BBC Radio 5 live sports extra.
Britain's Murray is also aiming to stay ahead of Serb Novak Djokovic in the contest to be the year-end number one.
Croatia's Marin Cilic plays Swiss US Open champion Stan Wawrinka in the day's second singles match at 20:00.
The top two players in the group after Friday's final round-robin matches will progress to the last four.
|John McEnroe Group qualification scenarios (Wednesday):|
|Murray qualifies if he defeats Nishikori, and Cilic defeats Wawrinka|
|Murray qualifies if he defeats Nishikori, and Wawrinka defeats Cilic in three sets|
|Nishikori qualifies if he defeats Murray, and Wawrinka defeats Cilic|
|Nishikori qualifies if he defeats Murray, and Cilic defeats Wawrinka in three sets|
Murray impressed in a straight-set win over Cilic in his opening match on Monday, but Nishikori was equally dominant against Wawrinka.
"To win against a player like Stan with that scoreline, I don't think Stan had really any chances on Kei's serve," said Murray, 29.
"I would say this is probably his best year that he's had on the tour. He's one of the best players in the world. He's been playing very well the last few months especially."
Fifth seed Nishikori, 26, beat Murray over five sets in the US Open quarter-finals in September, although the Scot won their other two matches this year at the Davis Cup and Olympic Games.
Murray is on a 20-match winning streak and will end 2016 as the world number one if he matches Djokovic's results in London.
He has been reunited with coach Ivan Lendl this week for the first time since the US Open, but there has been little talk about rankings, preferring to concentrate on the job in hand.
"I spoke to him about it on the Saturday night in Paris," said Murray.
"We spoke on the phone about it, then about moving forward for the end of this year and stuff - but since we've been here, I haven't spoken with the team about it."