Andy Murray’s desire to win the Barclays ATP World Tour Finals for the first time will tonight collide with Novak Djokovic’s ambitions of scoring a fifth successive title, and a record-equalling sixth overall. Whoever wins this evening will also be the year-end No. 1 in the Emirates ATP Rankings.

Murray has never been afraid to stand apart. In an age of instant gratification, when some people barely have the attention span to finish reading a tweet, Murray is embracing long-form content.

So prepare for the possibility of another Murray match exceeding three hours, which would be the third of its kind this week. Who knows, he and Djokovic might even push on tonight and break four hours. Murray has only been the No. 1 for a fortnight, with this his first tournament since that elevation in status, but he has certainly been filling his time at the top with tennis. No one could ever accuse Murray, should he lose to Djokovic this evening, of not making the most of being No. 1. Already he has been involved in a couple of classics, against Kei Nishikori in Group John McEnroe on Wednesday and then in yesterday’s semi-final against Milos Raonic. Contrast with Djokovic, who needed a little over an hour last night to defeat Nishikori.

So one consideration today will be how Murray’s body holds up. Here’s what’s not in doubt: Murray’s willpower.

Of course, the time period that Murray really wishes to extend is how long he spends on the apex of the Emirates ATP Rankings. Anyone who makes it to No. 1 has accomplished something extraordinary. This is a very exclusive club, with Murray only the 26th man of any nationality, and the first Briton, to have achieved the ranking. But there’s a club that’s even more elitist, which is restricted to those who have been the year-end No. 1. Beat Djokovic and Murray will put himself in the pantheon by becoming only the 17th man to finish a year in that position since 1973.

He’ll have his coach, Ivan Lendl, and his boyhood idol, Andre Agassi, for company. As well as Roger Federer, Rafael Nadal, Pete Sampras, Jimmy Connors, John McEnroe, Bjorn Borg, Stefan Edberg, Ilie Nastase, Mats Wilander, Lleyton Hewitt, Gustavo Kuerten, Jim Courier and Andy Roddick. And, of course, he would join Djokovic, who has hopes of being the year-end No. 1 for a third consecutive year, and for the fifth time overall, which would be the same number as Federer and Connors. Then the only man ahead of him on that leaderboard would be Sampras, who finished six consecutive years as the No. 1.

There hasn’t been a switch in the No. 1 ranking at a season finale since the 2001 tournament in Sydney, which was the year Hewitt moved above Kuerten (though that change didn’t come about through a final). Had Raonic taken his match point against Murray yesterday, Djokovic would already be assured of returning to No. 1, only a fortnight after being deposed. But now, if he is to regain that status, he must go through Murray himself.

This will be Murray and Djokovic’s first meeting for five months, going back to the Roland Garros final in June. Djokovic won that match to complete his career Grand Slam and become the first man since Australia’s Rod Laver in 1969 to hold all four majors simultaneously. This has been a season of two distinct halves. There’s no doubt that Djokovic was the dominant figure in the first few months of 2016 – Roland Garros was the sixth of his seven titles he has won so far this year, which have included four ATP World Tour Masters 1000s. And Murray has been imperious in the second half. This summer, he put together a 22-match winning streak, which brought him titles at The Queen’s Club, Wimbledon and the Olympics, and also took him into the final of the ATP World Tour Masters 1000 event in Cincinnati.

But now, after surviving yesterday, Murray is on an even longer run – 23 matches. After winning titles in Beijing, Shanghai, Vienna and Paris, Murray could today score a fifth consecutive title.

On both sides of the net, there are astonishing numbers to consider, with Djokovic seeking a fifth consecutive title at the season finale. Once you add in Djokovic’s triumph in 2008, when this tournament was staged in Shanghai, the Serbian is attempting to equal Federer’s record of six titles. The FedEx ATP Head2Head also makes for good reading for Djokovic, as he leads 24-10. Murray’s last victory over Djokovic was in the final of the clay-court ATP World Tour Masters 1000 in Rome. His last hard-court win over Djokovic was at the ATP World Tour Masters 1000 in Canada in August 2015.

Just to add another layer of intrigue, tonight’s tennis will also bring about the resumption of another rivalry, even if they are now coaching rather than playing: that’s Lendl versus Boris Becker. Three times Lendl and Becker met for the title at the season finale, with Lendl victorious at the 1985 and 1986 tournaments and Becker winning in 1988. In all, Lendl played in nine straight finals at this tournament, winning five of them. And now Murray – who was a beaten semi-finalist in 2008, 2010 and 2012 – has his first swing at this title.

A perfect finish is how Murray has described the two best players in the world meeting in the last match of the season, with the No. 1 in the Emirates ATP Rankings on the line. But, from his perspective, perfection will only truly be achieved through victory.

No. 1 Andy Murray vs. No. 2 Novak Djokovic
HISTORIC MATCH: The final match of the ATP World Tour season between No. 1 Andy Murray and No. 2 Novak Djokovic will determine the No. 1 player in the Emirates ATP Rankings in 2016. This is the first time since the 2000 ATP Finals in Lisbon, the year-end No. 1 player will be decided by the outcome of the championship match. That year, Gustavo Kuerten defeated Andre Agassi in the final to finish No. 1 ahead of Marat Safin.

NO. 1 AT STAKE: While Murray is trying to become the 17th player in the history of the Emirates ATP Rnakings to finish No. 1 , Djokovic is attempting to finish No. 1 for the third straight season and fifth time in six years.  Pete Sampras (six times), Jimmy Connors and Roger Federer (five times each) are the only players to finish No. 1 at least five times.

TITLE LEADERS: Djokovic is trying to capture his fifth straight Barclays ATP World Tour Finals title and sixth overall, which would tie Federer. Djokovic, Ivan Lendl and Sampras all have won five titles.

HEAD-TO-HEAD: Djokovic leads the rivalry 24-10 and this is their first meeting since the Roland Garros final on June 5, which Djokovic won in four sets. This is their fifth meeting of the season (Djokovic leads 3-1). Besides Roland Garros, Djokovic also won in the final at the Australian Open and ATP Masters 1000 Madrid. Murray’s lone win came in the final at ATP Masters 1000 Rome. This is their second meeting at the ATP Finals. In 2012, Djokovic won 46 63 75 in the second round robin match en route to the title.

ON COURT TIME: Murray has been on court 9 hours and 56 minutes, including the two longest best-of-three set matches on record in ATP Finals history. He won a 3h, 38m battle over Raonic in the semi-finals and 3h, 20m second round robin match over Nishikori.  Djokovic has been on-court 6 hours and 33 minutes during the week, including 1:10 vs. Goffin and 1:06 vs. Nishikori in his last two matches. His longest match was 2h, 14m vs. Raonic on Tuesday.

NO. 1 VS 2 FINALS IN ATP FINALS HISTORY: This is the seventh ATP Finals title match between the No. 1 and 2 ranked players (since 1973 when rankings began). This is the fifth 1 vs. 2 final at The O2 since 2010:
2016 – No. 1 Murray vs. No. 2 Djokovic
2014 – No. 1 Djokovic d. No. 2 Federer
2013 – No. 2 Djokovic d. No. 1 Nadal
2012 – No. 1 Djokovic d. No. 2 Federer
2010 – No. 2 Federer d. No. 1 Nadal
1986 – No. 1 Lendl d. No. 2 Becker
1983 – No. 2 McEnroe d. No. 1 Lendl

UNDEFEATED FINALISTS: This is just the eighth time in the round robin format that the two finalists have gone through the tournament undefeated. This is the fourth time since 2010 at The O2 this has occurred (2010, 2013-14, 2016). It also occurred in 1972, 1974, 1986 and 1993.

NO. 1 IN LONDON: With Murray into the final, the No. 1 player has reached the final of the Barclays ATP World Tour Finals the past five years, which is the longest streak in tournament history. Djokovic was No. 1 winning the title in 2012 and 2014-15 and Rafael Nadal was No. 1 in 2013 when he was runner-up. The previous best stretch of the No. 1 player reaching the final was four consecutive years from 1984-87 with John McEnroe winning the title in 1984 and Ivan Lendl from 1985-87.

NO. 1 CHAMPIONS: Nine different No. 1 ranked players have won the ATP Finals a total of 18 times since 1973 when the Emirates ATP Rankings began (Murray is trying to add his name to the list). Note: Of 26 players to rank No. 1 (since 1973), overall 13 won the ATP Finals title. Here are the others to win the title when not ranked No. 1 at the time:  Gustavo Kuerten (2000), Boris Becker (1988, ’92, ’95), Andre Agassi (1990) and Stefan Edberg (1989).

MATCH POINT SAVED WINNER: Murray is trying to become the first player win the ATP Finals after saving match point since Roger Federer in 2010. He saved three match points in his 46 76(8) 64 round robin win over Andy Roddick. He defeated Nadal in the final.