The ATP World Tour comes screeching to a halt in London over the next week with ATP's biggest showpiece. We take a look at the favourites…
The top eight in men's tennis descend upon the hard courts of the 02 Arena in London for a season-ending swansong.
World number one Novak Djokovic is looking to make it four wins in a row at the prestigious event. However, this will arguably be his toughest assignment, given the quality of the field and the group format.
The eight players are divided into two groups of four, with each group competing in a round robin format. The winners and runners-up of each group will then advance to the semi-final stage, where the two group winners play the runners-up for a place in the final.
Group A consists of Djokovic, Roger Federer, Tomas Berdych and Kei Nishikori. Djokovic has had a year to remember on court and arrives in the English capital with an impressive 22 match winning streak which earned him four straight titles.
The ten-time grand slam winner opens his account against Nishikori on Sunday, a player who has shown in the past he can go toe-to-toe with the best. Djokovic enjoys a 20-2 head-to-head record over Berdych, but the real threat is from world number three Federer.
The Swiss Maestro has troubled Djokovic at times this year, most notably in the Cincinnati Masters final where his hyper-aggressive style paid dividends as he denied Djokovic the only Masters title missing from his burgeioning trophy cabinet.
In Group B, we have Andy Murray, Stan Wawrinka, Rafael Nadal and David Ferrer. Murray begins a very busy two weeks as he will be practicing for the Davis Cup final at the end of the month on clay while trying to remain competitive on the faster hard courts as well.
Fortunately for the Scot, he starts the Tour Finals against seventh seed David Ferrer, whom he has already defeated twice in 2015 and enjoys a 11-6 head-to-head advantage.
The sleeping giant of the group is Wawrinka. The reigning Roland Garros champion is one of only five players to have defeated the indomitable Djokovic this year – albeit on clay – though he has remained quiet since his win in France, only picking up an ATP 500 title in Japan.
Nadal has been on the mend of late and has fought his way back up to fifth in the world rankings having been ranked tenth in July. The Spaniard picked up a confidence-boosting title at the German Tennis Championships and was competitive enough in the recent Paris Masters.
Now on the biggest stage, it would be the perfect time for the 14-time grand slam winner to shine.