LONDON (AP) -- Roger Federer got back on track at the ATP Finals, beating Matteo Berrettini 7-6 (2), 6-3 on Tuesday for his first victory of the round-robin stage.
Federer lost his opening match to Dominic Thiem on Sunday but the six-time champion looked sharper against Berrettini, never dropping his serve and hitting 24 winners.
Federer has failed to reach the semifinals only once in his previous 16 appearances, in 2008, but may still have to beat Novak Djokovic in his final group match on Thursday to advance.
Djokovic, who beat Berrettini on Sunday, faced Thiem in the evening match.
Federer earned the only break point of the first set at 6-5, but the Italian saved it with a forehand volley. In the tiebreaker, Berrettini double-faulted to hand Federer a 5-2 lead and netted a forehand rebound on set point.
Federer broke Berrettini to open the second set, but had to overcome a slight wobble at 4-3. Federer trailed 15-40 in that game and had to save three break points in total before holding with an ace.
He broke again to seal the win when Berrettini netted a forehand.
Berrettini's slim hopes of advancing would be over if Thiem wins at least a set against Djokovic later.
The Italian is making his first appearance at the season-ending event for the world's top eight players. But mistakes have hurt him in both matches, as he finished with 27 unforced errors against Federer - only one fewer than against Djokovic.
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