Serena, Osaka book US Open final rematch in Toronto quarter-final
It would be the first match between Naomi Osaka and Serena Williams since the Japanese star defeated her childhood idol 6-2, 6-4 in last year's US Open final
Reigning US and Australian Open champion Osaka broke at love in the final game to defeat Polish teen Iga Swiatek 7-6 (7/4), 6-4 after one hour and 51 minutes.
World number 10 Williams was broken twice and dropped the first three games in 10 minutes then battled back to defeat Russia's 48th-ranked Ekaterina Alexandrova 7-5, 6-4 in 91 minutes.
That set the stage for Williams, a 37-year-old American who will try for a record-tying 24th Grand Slam singles title at the upcoming US Open, to again face Osaka after the controversial finish to their Grand Slam showdown last year in New York.
It would be the first match between Osaka and Williams since the Japanese star defeated her childhood idol 6-2, 6-4 in last year's US Open final, a match marred by an on-court dispute between Williams and the umpire that led to a game penalty against Williams.
Osaka was booed by some fans during the awards ceremony and later dubbed what should have been her moment of glory "a little bittersweet."
Williams spoke after her match but before she knew who she would face in the quarter-finals, saying either Osaka -- who could return to the world number one ranking next week -- or Swiatek would be worthy foes.
"It will be a good match, whoever wins," Williams said. "Both players are playing well in this tournament in particular, so I'll be ready for her."
Alexandrova broke Williams -- the 2001, 2011 and 2013 Canadian champion -- in the first and third games for a 3-0 edge only to have Williams roll through the next four games.
They held from there until the final game of the first set, when the Russian's eighth double fault handed Williams the set after 46 minutes.
"(Alexandrova) hit really, really hard and she was hitting a lot of winners, so I was just happy I was able to just fight through that," Williams said.
Alexandrova broke Williams again to open the second set, but the US star pulled level in the sixth game and broke again in the 12th to advance after 91 minutes.
"I'm feeling good," Williams said. "Just hopefully just being able to stay in the rhythm and playing this week and next week would be good."
Williams said she is struggling with the transition from clay to grass to hardcourts more than usual this year.
"I definitely feel like it takes a while to get back into the rhythm," she said. "So it definitely feels different, especially for me now. Usually, I don't feel that huge of a difference, but for whatever reason, I do this year."
Pliskova chases No. 1
Czech third seed Karolina Pliskova kept the pressure on Osaka in the battle to take the world number one ranking by also reaching the quarter-finals.
Pliskova eliminated Estonia's Anett Kontaveit 6-3, 7-5 to set up a last-eight clash with rising Canadian star Bianca Andreescu, who outlasted fifth-seeded Dutchwoman Kiki Bertens 6-1, 6-7 (7/9), 6-4.
Pliskova, 27, must reach the final to have any chance of taking the top spot next week. Otherwise, Osaka will claim the number one berth.
French Open champion Ashleigh Barty's stint as the world's top-ranked player was assured of ending after she was knocked out on Tuesday.
Defending champion and fourth seed Simona Halep of Romania, coming off a Wimbledon title last month, beat Russia's Svetlana Kuznetsova 6-2, 6-1 to book a quarter-final against Czech qualifier Marie Bouzkova, who ousted Latvia's Jelena Ostapenko 6-2, 6-2.