World number two Elena Rybakina came from a set down to defeat four-time Grand Slam winner Naomi Osaka on Tuesday and reach the WTA Toronto Masters semi-finals, where she will face fourth-ranked Coco Gauff. Gauff, a 22-year-old American, had a walkover into her first Canada semi-final when Switzerland's Belinda Bencic withdrew with a hip injury. Osaka and Rybakina staged a dramatic duel in their first ever meeting on tour. "I was trying to stay close on the score, trying not to think if I make a mistake, just keep going," Rybakina said. World number 13 Osaka, who took a break has not won a title since the 2021 Australian Open.