Andy Murray will face Novak Djokovic with the ATP World Tour Finals title and year-end number one ranking at stake on Sunday.

The 35th meeting between the pair will also be the first time the season finale has ended with the number one spot on the line.

Murray replaced Djokovic as number one earlier this month, and the Briton is on a 23-match winning streak.

"I'm really privileged to be a part of history on Sunday," said the Serb.

Djokovic has won the last four titles in London and will overtake Murray with another win.

He added: "We've known each other for so many years. This is maybe one of the biggest matches we will ever play, so let's enjoy it."

Murray said: "Sunday is the last day for a while, we get a break after that. I'll just give my best of what I've got. Hopefully it's enough."

BBC Radio 5 live tennis correspondent Russell Fuller

Murray has spent nearly three and a half hours more on court than Djokovic this week, and twice set a record for the longest match in tournament history. So his renowned resilience, fitness and mental strength will be sorely tested in the final against an old foe who is starting to play with real conviction again.

The two have not met since June's French Open final, where Djokovic beat Murray for the 13th time in 15 matches. Since then, Murray has been by some margin the better player. He has won four titles in four different cities in the past six weeks: a fifth might just be considered his most remarkable triumph of the season.

Recovery key for Murray”‹

Saturday's semi-final win over Milos Raonic brought Murray his best ever winning run of 23 matches, but it also came at a cost.

At a gruelling three hours and 38 minutes it set a tournament record, and came just four days after Murray spent three hours and 20 minutes on court with Kei Nishikori.

The Scot, 29, has spent a total of nine hours and 54 minutes on court during his four matches this week, compared to six hours and 31 minutes for Djokovic.

"I don't know how I'll feel on Sunday," said Murray, who headed to a nearby hotel rather than his Surrey home after the win over Raonic.

"The physical side, obviously the body is a bit sore after such a long match, but mentally it was tiring too."

Murray will at least hope to enjoy the same rapturous reception each time he has stepped on court this week, with crowds of 17,000 eager to salute the new number one.

"When you're out there competing, the atmosphere helps for sure," he said.

"Playing in front of a pretty packed crowd at this stage of the year definitely gives you an extra boost, helps you to keep pushing right to the end."

Flawless form boosts Djokovic

If Murray has been the leading force on the tour in the last six months, Djokovic has been utterly dominant at the O2 Arena for the last four years.

The 66-minute semi-final victory over Nishikori took his record to 22 wins in 23 matches at the O2, and he is going for a fifth straight season-ending title and sixth overall, to tie Roger Federer's record.

After beating Murray to win his first French Open title in June, the Serb suffered a slump in form, but he feels his best is not far away now.

"It's been going in the right direction," said Djokovic. "I'm very glad that I get to experience this feeling on the court.

"The last couple of matches have been pretty much flawless, and now we're coming up to the last match of the year that everyone anticipated and wanted."

Djokovic has the edge - McEnroe

Djokovic leads the head-to-head 24-10 and has won 13 of their last 15 matches, including victories in the finals of the Australian Open, Madrid Open and French Open this year.

However, Murray beat the Serb to win his first Italian Open title in May and surged past him in the rankings by winning his last four tournaments.

Speaking earlier in the week, three-time Finals champion John McEnroe told BBC Sport: "Novak still has a decided edge in the bigger matches and a much better head-to-head.

"That would lead me to believe that if they walk on the court on Sunday in the finals, he'd have a real chance to get things right in his mind and finish the year world number one.

"But Murray has done a lot of really great things to get to this place, and has been playing the best overall the last six months, so if there was a time when he's ready to finally make this step, it would be a hell of a place to do it."