|Venue: The 02 Arena, London Dates: 12-19 November|
|Coverage: Watch live on BBC Two, Red Button, BBC Sport website and mobile app, listen on BBC Radio 5 live sports extra and follow text updates online.|
Bulgaria’s Grigor Dimitrov admitted he had felt “pretty nervous” after seeing off Austrian Dominic Thiem in three dramatic sets on his ATP Finals debut.
Sixth seed Dimitrov beat fourth seed Thiem 6-3 5-7 7-5 in the opening round-robin match in the Pete Sampras Group.
Dimitrov failed to serve out the match at the first time of asking, only for Thiem to hand him a second opportunity with two double faults in a row.
Rafael Nadal takes on David Goffin in the second singles match at 20:00 GMT.
Roger Federer and Alexander Zverev won the opening matches in the Boris Becker Group on Sunday.
The pair will meet in Tuesday’s second singles match at 20:00 GMT, after Marin Cilic plays Jack Sock at 14:00.
‘I’m not going to lie – I was pretty nervous’
Dimitrov, 26, just about held his nerve to win a gripping battle of the one-handed backhands against Thiem, who is playing in the Finals for the second year running.
It was the Bulgarian who had the edge for most of the contest, breaking serve once to win the first set and not facing a break point until the end of the second.
However, Thiem took his chance in the 12th game to draw level and force a third set, before breaking back when Dimitrov served for the match at 5-4 in the decider.
Dimitrov missed a chance to earn two match points when he failed to challenge a ball that had missed the baseline, but the former junior Wimbledon champion recovered his poise to break for a third time in game 11, eventually converting his third match point after two hours and 19 minutes.
“I’m not going to lie – I was pretty nervous, my first match out here,” said Dimitrov.
“I’m just very grateful to win that match, especially in that manner. It’s never easy to come out here and play for the first time.”