Back spasms forced Serena Williams to close the curtain on the Toronto final, but she still plans to give Cincinnati a shot.

The 37-year-old Williams retired from today's Rogers Cup final while trailing 19-year-old Canadian Bianca Andreescu, 1-3, after 13 minutes of play.

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The 10th-ranked Williams said she plans to travel to Cincinnati to try to play the Western & Southern Open as her final preparation for the US Open.

"As of now, I'm going to go to see what happens," Serena told the media in Toronto.

Williams was bidding for her 73rd career title, but grew tearful after experiencing the back spasms and retired.

The fact Williams was playing for the fifth straight day—and playing her first day match after four evening matches—may have contributed to her back issues, which she said can pass in 48 hours.

"That's the most frustrating part is that I've had these awful spasms a lot in my career, actually," Williams told the media in Toronto. "And they're incredibly painful, but it goes away after, like, 24, 36, maybe 48 hours, and like clockwork. So I do different treatments. I take a day off.

"But obviously, I didn't have 24 hours or plus to take off. But in that first phase, it is incredibly painful, to a point where I usually don't get out of bed. So if it's what typically happens, I will be fine, but I have to wait and see."

Photo credit: Rob Newell/CameraSport