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Roger Federer saves all three break points en route to beating Matteo Berrettini at the Nitto ATP Finals.

Federer Up & Running In London

Swiss defeats Berrettini on Tuesday Group Bjorn Borg

Roger Federer declared that he's "not allowed to lose anymore" after dropping his opening match to Dominic Thiem at the Nitto ATP Finals. The Swiss stuck to his rule on Tuesday, prevailing 7-6(2), 6-3 against Italian Matteo Berrettini in Group Bjorn Borg.

”It’s unusual to lose and then come back to play again, but I did it last year, so I have some experience,” Federer joked. “I’m very happy with how I played today. Matteo was always going to be difficult with his big serve… I was pretty clean in my own service games and I think that helped today. I hope I can keep it up and maybe even play a bit better in the next match.”

The 38-year-old Federer improved to 2-0 against Berrettini their FedEx ATP Head2Head rivalry, including a straight-sets victory this year at Wimbledon. The Swiss has more match wins (58) and titles (6) than any player in Nitto ATP Finals history. Federer, who fell to Dominic Thiem on Sunday, is 17-0 lifetime in his second round-robin match at this event.

”There's no reason to be too down [after losing to Thiem]. We came here to play three matches and give it all we have. It was the big goal of the season to qualify here, which we did," Federer said. "I had a day off and there’s plenty of ways to get rid of that loss. Hanging out with my kids will do that for me. I was ready and prepared today. That’s what matters the most right now.”

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The match result also impacts Dominic Thiem's chances at advancing out of round-robin action. He'll qualify for the semi-finals if he defeats Novak Djokovic in Tuesday's night session. Thiem is bidding to become the first Austrian semi-finalist at the year-end championships since the event added semi-finals and finals in 1972.

Berrettini, who lost to Djokovic on Sunday, is still looking to become the first Italian to win a match at the season-ending championships.

Federer earned the lone break point of the first set at 6-5, but Berrettini erased it with a forehand winner. The Swiss drew first blood in the tie-break and earned a 2/1 mini-break advantage after Berrettini overcooked a forehand. Federer raced through the final three points of the set to grab the early lead after 42 minutes. The six-time champion is 21-7 in tie-breaks this season. 

He continued to ride the momentum and broke the Italian to love in the opening game of the second set. Berrettini had a chance to level the match with Federer serving 4-3, but couldn't convert three break points. A slice forehand from Berrettini found the net in the next game and wrapped up play after 78 minutes.

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