TORONTO, Canada - World No.1 Karolina Pliskova is through to the quarterfinals at the Rogers Cup for the first time, moving past fellow big-server Naomi Osaka after the Japanese player had to retire early in the third set.

Qualifier Osaka, a promising Japanese teenager with a big game, did very little wrong in their hour and 46 minute battle, even extending the match to a third set, but was undone by the return of a lingering abdominal injury trailing 6-2, 6-7(4) 1-0.

Despite the unfortunate end to an otherwise thrilling match, Pliskova can take away plenty of positives, including a dominant serving performance which saw her blast 12 aces against the Japanese player. She broke Osaka four times, and saved all three of the break points she faced. 

The victory marks Pliskova’s 70th career match firing 10 or more aces. It’s also the 10th match of 2017 where she’s hit 10 or more aces, second most only to her sister Kristyna Pliskova, who has reached the figure in 11 matches.  

Also, after today's match, Pliskova will return to the top of the WTA aces leaderboard, overtaking Julia Goerges.

For Osaka, it’s a disappointing turn of events after battling through the qualifying rounds and taking a set off the World No.1. Osaka, who had to withdraw from events in Prague and Madrid with the same injury, heeded the advice of her coach and tournament doctors, and retired soon after edging through in the second set tiebreaker.

Earlier in the season at Wimbledon, Pliskova beat out Simona Halep in the race to take Angelique Kerber’s WTA World No.1 ranking, but even in her first tournament since rising to No.1 Pliskova is facing the challenge of hanging on to the top spot.

"It's going to be tough," the 25-year-old told "There are a few tournaments to go before the end of the year and I know Simona's behind me. I'll do my best to stay there as long as I can - hopefully a few more weeks."

Up next for Pliskova, the top seeded Czech will take on the winner between No.6 seed Caroline Wozniacki and No.10 Agnieszka Radwanska for a spot in the semifinals.

More to follow...