A 6-4 6-3 victory over Kevin Anderson ensured Roger Federer progressed to the last four of the ATP Finals for the 15th time in his career.
Roger Federer exacted a modicum of revenge for his Wimbledon loss to Kevin Anderson by beating the South African in straight sets to seal his berth in the last four of the ATP Finals.
The Swiss suffered a quarter-final loss to eventual runner-up Anderson at SW19, losing the final set 13-11, but he improved his record to 5-1 in head-to-heads with the tall South African in London on Thursday.
Federer converted each of his two break points in the first set and then reeled off four games in a row to claim the second and seal a semi-final berth at the season-ending tournament for a 15th time.
Anderson had already qualified for the last four, with Federer ensuring he finished top of their group to join both his opponent and Novak Djokovic in the knock-out phase.
Federer won each of his first two service games without dropping a point as he continually pushed his opponent deep and forced him to swoop down low for shots.
The Swiss would have fallen 0-40 down at 2-3 had Anderson stuck away a backhand, though, and Federer showed him how it should have been done with a winner down the line to hold.
Anderson was then broken for the first time as he produced a costly double fault when 0-40 down, only to respond with a break of his own when Federer whipped a forehand wide.
Yet three unforced errors gave Federer the chance to break again and he dropped an exquisite volley over the net to move 5-4 ahead before staving off three break points in the next game en route to claiming the opener.
It was not until the seventh game of the second set when Federer had a chance again and he made it three break-point conversions out of three when Anderson crashed a backhand into the net after being pinned back on the baseline again.
Federer was unable to claim the victory with either of his first two match points but, at the third time of asking, Anderson found the net to hand the Swiss the victory.
— ATP World Tour (@ATPWorldTour) November 15, 2018
Federer  bt Anderson 
Federer – 18/14
Anderson – 13/24
Anderson – 10/2
BREAK POINTS WON
Federer – 4/6
Anderson – 1/4
FIRST SERVE PERCENTAGE
Federer – 58
Anderson – 55
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Federer – 79/62
Anderson – 73/32
Federer – 61
Anderson – 44