Roger Federer is now one win away from retaining his title at the ATP World Tour Finals after a 7-5 6-3 success over David Ferrer.
The Swiss, looking to triumph in the season-ending tournament for a record sixth time, extended his unbeaten record against the Spaniard to 12-0.
Ferrer did make the fourth seed work in a first set that lasted the best part of an hour, but his exertions from the previous night, when he lost to Tomas Berdych in three, left him struggling to live with Federer.
“Obviously I am very happy to have played so well again. That is what it takes to beat David; he has had an amazing season and an amazing tournament,” said Federer afterwards.
“He can still win the Davis Cup next week, so I hope he does that.”
Federer will now face the winner of the semi-final tie between Jo-Wilfried Tsonga of France and Czech Tomas Berdych on this evening.