Tomas Berdych and Kei Nishikori played out the first three-set encounter of this week's ATP World Tour Finals this afternoon, with the latter recording a 7-5 3-6 6-3 win in the English capital.

It seemed that having taken the first set with a crucial late break and then opening up a 2-0 lead in the second, Nishikori was going to produce a routine triumph at the O2 Arena.

However, for the remainder of that set Nishikori, who at 25 is the youngest of the eight players involved in the tournament, struggled with his service game.

Former Wimbledon finalist Berdych took full advantage of his Japanese opponent's loss of form to win the next five games in succession, before he eventually forced the encounter into a deciding third set.

Proceedings went with serve until the eighth game when trailing 3-4 and 15-40, the serving Berdych sent a routine forehand into the net, which handed Nishikori the opportunity to serve for the match.

The eighth seed and 2014 semi-finalist duly converted that chance, serving out to love to clinch the victory in just shy of two hours and 30 minutes.

To stand any chance of reaching the last four again, it is likely that Nishikori will need to beat Roger Federer, who is up against world number one Novak Djokovic this evening. As for Berdych, even a victory against Djokovic on Thursday is unlikely to be enough to extend his interest in the competition beyond the group stage.