World No 1 ready to face Goffin despite knee problem even as Swiss master proves too good for Sock at O2 Arena
World Tour Finals: Nadal ready to return to court after Federer wins
Even as Rafael Nadal said he was ready to give it a go at the ATP World Tour Finals on Sunday, Roger Federer made a strong start to his bid to cap his golden year with a seventh title as he defeated Jack Sock 6-4, 7-6.
Nadal, twice a Tour Finals runner-up, is due to open his campaign against David Goffin on Monday. However he conceded he was still struggling with the knee problem that forced him to pull out of the recent Paris Masters.
With defending champion Andy Murray, Novak Djokovic and Stan Wawrinka all absent from the Tour Finals due to injury, Federer and Nadal are the unquestioned headline acts.
Having won the French and US Opens this year, Nadal has matched Federer's unexpectedly dominant run - including title wins at the Australian Open and Wimbledon - as the old rivals hoovered up all four of this year's grand slam crowns.
He is already guaranteed to finish as the year-end No 1 for the first time since 2013, making the 31-year-old Spaniard the oldest man to earn that honour.
But his hopes of finally winning the Tour Finals for the first time could be hampered by injury.
Speaking after receiving his year-end No 1 trophy following the Federer match, Nadal said he was keen to go out on court.
"It has been a fantastic season, a very emotional one after all of the things I have been going through in the last couple of years with injury," he said. "To have this trophy again is something I never thought was possible. See you tomorrow on court."
Meanwhile, Federer was at his imperious best on Sunday.
Four months after winning Wimbledon for a record eighth time just a few kilometres across London, he was back in the English capital aiming to cap a remarkably successful spell by lifting the silverware at the O2 Arena.
But after seeing off Sock in his group opener, the world No 2 has now won his last 11 matches.
That dominant streak has already earned him titles in Shanghai and Basel, and he hopes to maintain that hot streak all the way to the Tour Finals crown next weekend.
"It's wonderful to be back, especially after missing last year with injury," Federer said. "I got off to a great start, but the second set was tight.
"The breaker could have gone either way and in the end he helped me with some mistakes. I'm really happy I got through somehow."
Federer was back in the groove against Sock, who had grabbed the last Tour Finals berth by winning his first Masters title in Paris earlier this month.
Even the 25-year-old American, yet to make it past the last 16 at any major, was caught off guard by his climb to a career-high ninth in the rankings.
He was forced to cancel a scheduled round of golf at Augusta as he instead prepared to face Federer.
A relaxing stroll around that famous course might have seem preferable to facing Federer, who had not lost a set in their three previous meetings and quickly took charge with a break in the first game.
That was all the advantage Federer needed as the 19-time grand slam champion swept through the first set with 10 winners and four aces.
Federer did not have it so easy as Sock found some rhythm in the second set, but the Swiss held his nerve to take it in a tie-break.