Novak Djokovic and Roger Federer prepared to face off for a place in the last four of the ATP Finals on Thursday after Matteo Berrettini made history with a consolation win in London.
The heavyweights, who have won the season-ending tournament 11 times between them, will meet for the 49th time in a repeat of this year's Wimbledon final.
Djokovic, who holds a 26-22 advantage, has won their past five meetings, including their epic five-set battle in the final at Wimbledon in July, during which he saved two championship points.
The Serbian is bidding to equal Federer's record of six ATP Finals titles and is also challenging Rafael Nadal for the year-end number one ranking.
The second seed, 32, will leapfrog Nadal to finish in the top spot if he wins the title at the O2 Arena and Nadal does not reach the final.
The Serbian, who can claim a record-equalling sixth year-end number one finish, is hungry to finish the year on top.
"One of the two biggest achievements that you can have as a ...
