|ATP World Tour Finals|
|Venue: O2, London Dates: 15-22 November|
|Friday 20 November: 14:00 GMT - Rafael Nadal v David Ferrer. Live on BBC Two and BBC Sport website|
|20:00 - Andy Murray v Stan Wawrinka. Live on BBC Radio 5 live sports extra and BBC Sport website|
Britain's Andy Murray will take on Switzerland's Stan Wawrinka for a place in the last four of the ATP World Tour Finals in London on Friday.
They meet in the last round-robin match at 20:00 GMT, with the winner facing Roger Federer in the semi-finals.
A victory would also guarantee Murray the year-end world number two ranking for the first time.
World number one Novak Djokovic will play 14-time Grand Slam champion Rafael Nadal in Saturday's other semi-final.
Semis within sight again for Murray
Murray will travel to Belgium next week for Great Britain's first Davis Cup final since 1978, but he has yet to reach the London final in five previous attempts at the O2 Arena.
The Scot, 28, has the chance to reach his third semi-final but must recover from a poor performance against Nadal on Wednesday.
"Obviously I lost comfortably to Rafa and I could play him in a couple days' time and it could be a different story," said Murray.
"I'm trying to win every match that I play. I hope that's how all of the players view it."
Wawrinka lost to Nadal in his opening match but saw off David Ferrer on Wednesday.
The 30-year-old Swiss trails 8-6 in career meetings with Murray but they have not played since 2013, since when Wawrinka has won Grand Slam titles in Australia and earlier this year in France.
"We used to have some big battles in the past, some tough matches, three sets, four sets," Wawrinka said.
"It's going to be interesting how I'm going to play Friday, if I'm going to bring the positive game that I started to play on Wednesday, and also how he's going to be.
"He's having an amazing year, number two in the world and so dangerous indoors, especially at home. So we'll see."