MASON (Ohio) • Roger Federer and Novak Djokovic overwhelmed opponents at the Cincinnati Masters on Tuesday, when Serena Williams withdrew because of back trouble.
She had hoped to recover from the spasms that forced her out of the Rogers Cup final in Toronto on Sunday. She lasted only four games before retiring.
But the 23-time Grand Slam champion said her back was "still not right", casting a further shadow on her chances at the US Open starting on Aug 26.
For Djokovic and Federer, playing for the first time since the Serb's victory over the Swiss in the Wimbledon final, it was a smooth start to their US Open build-up.
Third seed Federer was unruffled despite a one-hour rain interruption at 2-2 in the second set, eventually defeating Argentina's Juan Ignacio Londero 6-3, 6-4 to reach the third round at an event where he is a seven-time winner.
"I'm very happy, even if it was a bit tricky with the rain delay," Federer said. "This is the start of a long, long hard-court swing. It's good to begin with a win.
"I didn't know that much about my opponent - he's new to the tour - but you have to concentrate on your own game."
Defending champion Djokovic double-faulted three times as he dropped serve in the opening game against American Sam Querrey but quickly put things right and pulled away for a 7-5, 6-1 victory.
"I ended the match well even if the start was nervy," said Djokovic, who broke Querrey twice to take the first set before easing to victory.
"Sam was feeling comfortable on the court at the start and dictating. It was tough facing his big serve."
Djokovic faces Spanish qualifier Pablo Carreno Busta, who withstood 32 aces from John Isner and a match point before beating the American 6-4, 6-7 (1-7), 7-6 (8-6).
Williams, meanwhile, was left just trying to get healthy after pulling out of her first-round tie against qualifier Zarina Diyas.
"I came on Sunday and have tried everything to be ready to play tonight, and was still hopeful after my practice this morning," the American said. "But unfortunately my back is still not right."
It is another injury blow for the 37-year-old, who was hampered by knee trouble earlier this term and remains in search of her first title since the 2017 Australian Open.
Her compatriot Coco Gauff, the 15-year-old who made a magical run to the fourth round at Wimbledon last month after getting a wild card into the qualifiers, received another wild-card entry on Tuesday for the US Open's main draw.
Age restrictions on the women's professional tour limit the number of tournaments someone aged 15 can enter, as well as the wild-card invitations she can be offered and the world No. 140 already has had three elsewhere.
But the WTA says that the US Tennis Association, which runs the Grand Slam tournament and so is not overseen by the WTA or men's ATP tour, can choose to ignore the eligibility rule and offer the player a wild card.
AGENCE FRANCE-PRESSE, ASSOCIATED PRESS
ATP CINCINNATI MASTERS
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