Osaka retires with back pain, Giorgi downs Raducanu in Toronto

TORONTO : Naomi Osaka retired with lower back pain from her opening match while defending champion Camila Giorgi beat Britain's Emma Raducanu on Tuesday at the Toronto Open where Serena Williams' pending retirement from tennis dominated the proceedings.

Osaka, in only her second tournament back from a left Achilles injury, retired while trailing Estonia's Kaia Kanepi 7-6(4) 3-0 in her first match of the U.S. Open tune-up event.

"I felt my back from the start of the match, and despite trying my best to push through it I just wasn't able to today," said Osaka. "I'd like to pay credit to Kaia for playing well and want to wish her all the best for the rest of the tournament."

Osaka took a medical timeout while trailing 4-3 in the first set and appeared to be moving a bit better and actually broke Kanepi both times she was serving for the opening frame to force the tiebreaker.

Osaka spent more time working with the trainer during the changeover between sets and then quickly fell behind in the second before deciding to end the match.

"It's very tough to see that she has to retire this way," Kanepi, who will face Spanish eighth seed Garbine Muguruza in the second round, said during her on-court interview.

U.S. Open champion Raducanu went ahead 2-0 in the second set but Giorgi finished with a flourish as she secured the next six games with a mix of solid returns, net play and movement.

"This is my game and so I should play like this always but sometimes it doesn't work," Giorgi said during her on-court interview.

The two players exchanged six breaks of serve during the opening set before Giorgi flicked a switch and breezed through a tiebreak that came to a quick end after a Raducanu double-fault.

Up next for the 30-year-old Italian will