Stanislas Wawrinka has boosted his chances of reaching the semi-finals of the ATP World Tour Finals with a three-sets victory over Spain's David Ferrer.
There was little to separate the two players during the early exchanges of the first set, until Wawrinka broke the Ferrer serve to move 4-2 ahead.
However, Ferrer broke twice to take a 6-5 lead, before some strong returns from Wawrinka allowed him to take the set to a tie-break, which Ferrer won 7-3.
The world number three fell behind early in the second set when some aggressive play from Wawrinka saw him break in the third game.
The Swiss player maintained his advantage throughout the set, going on to serve it out 6-4.
The world number eight dominated the third set, forcing Ferrer into a string of unforced errors on his way to opening up a 5-1 lead.
Wawrinka broke Ferrer's serve for the third time to take the final set 6-1 and secure an important victory in Group B.