TORONTO • World No. 1 Serena Williams suffered just her second loss of the year after she was sent crashing out of the WTA Rogers Cup by Swiss teenager Belinda Bencic on Saturday.
In a clash between the oldest and youngest players in the draw, the 18-year-old stormed from behind to prevail 3-6, 7-5, 6-4.
Bencic closed out the tense, 2hr 28min showdown on her first match point, hitting a forehand winner to the open court.
She bent over and covered her face with both hands as she soaked up the biggest victory of her career so far.
"I can't describe the feeling right now," the world No. 20 said after snapping Williams' 14-match win streak in Toronto to book her final spot against second seed Simona Halep.
"I was very overwhelmed from the situation on the court, but I'm just so happy the forehand landed in and she couldn't reach it any more. It was an incredible feeling. I have no words."
Bencic is the youngest player to beat Williams since the American lost to a 17-year-old Maria Sharapova in 2004.
The 33-year-old Williams has enjoyed a dominant year, and went into the match with a 43-1 win-loss record. But the loss has cast a shadow over her pursuit of her fifth Major title in a row as she attempts to complete a calendar-year Grand Slam by retaining her title at the US Open, which begins on Aug 31.
A US Open crown would give her 22 Grand Slam singles titles, matching German legend Steffi Graf for the most in the Open era.
Williams had pulled out of the Stanford tournament last week with an elbow injury but said after her quarter-final victory in Toronto that it was no longer a problem.
The American had won in Toronto in her last two appearances in 2011 and 2013.
But she looked sluggish and troubled throughout much of the semi-final, failing to run down balls in the open court and often turning in frustration towards the stands to speak with her coach Patrick Mouratoglou.
Despite the defeat, Williams said she felt she was in charge of the points.
"I felt pretty much in control until I lost the match," said Williams, who had 12 double faults.
"I always felt I still had an opportunity to stay in there. And obviously I was down and stuff. But I just wasn't playing well today."
What she was not in control of at times were her emotions.
She had a meltdown in the second set, smashing her graphite racket to pieces after she double-faulted on game point to go down 3-5. And Bencic kept Williams off balance with precision ground strokes and a neat serve-and-volley game when she needed it.
"She never gives up and she fights hard," Williams said of Bencic, who also has Slovak citizenship through her parents.
The unseeded Bencic has now won 20 of her last 24 matches. She had to beat two other top-10 players (No. 5 Caroline Wozniacki and No. 6 Ana Ivanovic) to reach the semi-finals.
Halep advanced with a 6-4, 6-4 win over Italy's Sara Errani in 1hr 35min.
"I'm completely dead now, it was a very tough match," said Halep, who dropped to the court when Errani's return sailed long. "She played amazing, she was running everywhere for all the shots.
"I did everything I could to finish in two sets because in the third one, I don't know what would happen."
AGENCE FRANCE-PRESSE, REUTERS