• Serena Williams was forced to retire in the Rogers Cup final.
  • The veteran American played just four games before succumbing to back spasms, which saw Bianca Andreescu, 19, win the trophy in front of her hometown fans.
  • Williams broke down in tears when she withdrew from the match, and then again while making her post-match statements.
  • Andreescu wins 1,000 tour level ranking points and will reach a career-high rank of 14 on Monday.
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Bianca Andreescu, a 19-year-old Canadian, just beat Serena Williams in the Rogers Cup final after the veteran American was forced to retire after just four games because of back spasms.

Williams reached the tournament final having bounced back from a 6-1 opening set loss in Saturday’s semifinal to beat Marie Bouzkova two sets to one, one day after swatting aside Naomi Osaka in the quarterfinal stage.

At the Aviva Centre in Toronto, Ontario, Williams faced a foe for the first time in her career, the young but extraordinarily talented Andreescu, and even pleaded with fans the day before to show her some love because she knew she would be in an unpopular position having to battle against the hometown hero on Centre Court.

But just four games into the Rogers Cup final, also known as the Canadian Open – a Masters event worth 1,000 tour ranking points, Williams succumbed to injury and could compete no longer.

When Andreescu was 3-1 up in the first set, having broken Williams in the third game, Williams cried, walked to her chair, and called her trainer. She retired from the match.

The official reason is that she had suffered an injury to her upper back, she was having spasms, and just couldn't compete.

Read more: Serena Williams says she beat Naomi Osaka at the Rogers Cup because she had been watching her 'a lot' since US Open meltdown

Andreescu, who was born in nearby Mississauga, a mere 30 minute drive from the Aviva Centre, had won.

The local teenager was champion.

Watch it unfold here:

"I'm sorry I can't do it today, I tried but I just couldn't do it," Williams said through tears after the match, according to the WTA. "Thank you Jehovah for letting me come out here. Bianca you're a great sportswoman. Thanks to my team. "It's been a tough year, but we'll keep going."

Andreescu, who will reach a career-high world rank of 14 on Monday, said: "Serena you made me cry a bunch over there. I know what it's like to pull out of tournaments and be injured. I've watched you play so many times. You are truly a champion on and off the court.

"I'm speechless right now," she added. "I'm the first Canadian to make the final and win this tournament since 1969. This week has not been easy, I've had many many tough matches, and especially what I've been through the last two months hasn't been easy. I kept telling myself never give up."

Watch Andreescu lift the Rogers Cup right here: