Serena Williams Is Stunned in Toronto Semifinal

Photo Serena Williams while playing Switzerland's Belinda Bencic during their Rogers Cup semifinal match in Toronto. Credit Warren Toda/European Pressphoto Agency Top-ranked Serena Williams stumbled in the Rogers Cup semifinals on Saturday night in Toronto, falling 6-3, 5-7, 4-6 to the Swiss teenager Belinda Bencic.

The winner of the first three Grand Slam events of the season, Williams, 33, lost for only the second time in 45 matches this season. She won titles in Toronto in 2001, 2011 and 2013.

Bencic, 18, is unseeded at the tournament and ranked 20th in the world. She knocked off three seeded players to reach the semifinal. Bencic opened with a victory over Eugenie Bouchard of Canada and…