Second seed Federer recorded his 50th match win of the year with a 6-4, 7-6(4) victory over eighth seed Jack Sock in one hour and 31 minutes in their Group Boris Becker opener.
The Swiss ace who had taken a holiday after winning the Basel tournament for a record eighth time, is also in London in to campaign for a record eighth title ATP finals.
Federer capitalised on early nerves by Sock, winner of his first ATP World Tour Masters 1000 title at the Rolex Paris Masters seven days ago, with a service break in the first game. Sock grew in confidence by using his powerful forehand to pierce holes in Federer’s game, but he was unable to break back.
At 3-3, 30/40 in the second set, Sock struck a serve that jammed up Federer on a backhand return in a confidence-boosting hold. In the American’s next service game, he recovered from 15/40 — and saved five break points in total.
Federer, in contrast, lost just two of his first-service points through his first six service games of the second set. In the tie-break, as Federer edged closer to his 12th victory over a Top 10 players in the Emirates ATP Rankings this season, he opened up a 4/2 advantage. The encounter ended with Sock striking a backhand return long.
Federer is now 53-12 at the Nitto ATP Finals, which he first qualified for in 2002 when the tournament was played in Shanghai.
Federer improved to a 4-0 FedEx ATP Head2Head record against Sock, which also includes a win at the BNP Paribas Open in March.
*With reports by atpworldtour.com