Andy Murray added another win to his name after beating Fabio Fognini 62 64.
Murray, who is bidding to qualify for the season finale for the seventh year in a row, will next play against, will next play Kevin Anderson.
David Ferrer, who can also qualify to the finals in London like Murray, defeates Fernando Verdasco 6-3, 6-2.
Ferrer held serve through all nine of his service games and broke Verdasco thrice.
"The first set was very important," said Ferrer. "I played very well in the first games - when he was hitting the ball very hard - and it wasn't easy. I stayed solid in the second set took my chances."