|ATP World Tour Final|
|Venue: O2, London Date: Sunday, 22 November|
|18:00 GMT: Novak Djokovic v Roger Federer - live on BBC Two, BBC Radio 5 live sports extra and BBC Sport website|
Novak Djokovic will try to win a record fourth consecutive season-ending title when he takes on Roger Federer at the ATP World Tour Finals on Sunday.
Djokovic, 28, hopes to surpass Ivan Lendl, who won his third straight Tour Finals in 1987.
Federer will be buoyed for his 10th final in this event after beating Djokovic in the group stage on Tuesday.
The 34-year-old had been set to face the Serb in last year's final but had to pull out with a back injury.
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I don't feel unbeatable - Djokovic
Djokovic has won 81 matches, 10 titles and three Grand Slams in securing the end-of-season number one ranking for the fourth time in five years.
"It's the best season of my life," said the Serb. "Regardless of the outcome of Sunday's match, the season will still be the best that I had."
Rafael Nadal was brief and to the point when asked after their semi-final what Djokovic does so well, replying: "Everything."
Djokovic has lost just six times this year and will appear in his 15th consecutive final of 2015 at the O2 Arena on Sunday.
However, a three-year unbeaten run indoors - and 23-match winning streak - came to an end against Federer on Tuesday.
"I don't feel unbeatable, but it does definitely feel great when I'm playing the way I played," he said after his semi-final victory.
"When I feel like I'm dictating the pace, the match itself, most of the rallies, I feel like I'm on top of my opponent."
His confidence is higher - Federer
Federer has been the only player capable of regularly pushing Djokovic this year, winning three of their seven matches.
The Serb won their most significant clashes, in the finals of Wimbledon and the US Open, but Federer only has to look back five days to his last victory on the same O2 centre court.
"For me it's an advantage because I guess it gives me a bit of confidence," said Federer.
"For him it's an advantage because he gets a second chance, and he's in another final. He's played some great tennis since we've played.
"So I still believe his confidence is slightly higher than mine with the amount of success he's had this year."
There is at least little chance of a repeat of 12 months ago, when Federer had to inform the 17,000 spectators that he was unable to play the final.
"I'm feeling slightly better than last year," said the Swiss. "This year obviously it's very different. I feel completely normal. It's a big relief for me."