Ash Barty has officially been punted from the throne of Women’s tennis

Ash Barty has officially been punted from the throne of women’s tennis, but her overthrow has set-up a tantalising showdown for the No. 1 ranking.

Australian Ashleigh Barty’s eight-week reign as the WTA’s No. 1 player in the world is over after Naomi Osaka breezed past her German opponent in the second round of the Canadian Open.

Barty’s 6-7 (5-7) 6-3 6-4 second-round loss to American Sofia Kenin left the door open for the Japanese star and ex-world No. 1, who snatched the opportunity when Tatjana Maria retired injured after dropping the first set 6-2 in Toronto on Thursday.

But Czech Karolina Pliskova, another former world No. 1, could overtake both Osaka, the reigning US Open and Australian Open champion, as well as Barty, with a deep run in the tournament.

Pliskova, the first Czech ever to hold the top spot, opened her campaign in Toronto perfectly by beating Alison Riske, the American who snapped Barty’s 15-match winning streak in the Wimbledon fourth round last month.

The Czech defeated Riske 6-4 6-7 (4-7) 6-2 and will face Anett Kontaveit, whose previous opponent Carla Suarez Navarro retired while trailing 7-5 3-1, on Friday.

If Osaka reaches the quarter-final or semi-final, Pliskova would need to reach the final, or otherwise defeat her in the final to be No. 1.

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Osaka had not played a match since losing to Yulia Putintseva in the first round at Wimbledon.

“I thought I played really well despite the fact that we only played one set,” Osaka said. “I was able to do what I wanted, which was go for the shots that I had the opportunity to.

“And, of course, there were a couple unforced errors, but I think that’s part of the process.

“For me, I’m just happy that it was my first match in a while and I was able to get in the groove of things quickly.”

Ash Barty could be the World No. 3 by the end of the week.

Three-time champion in Toronto Serena Williams, who has said she wants to get more matches in before seeking a record-equalling 24th career grand slam title at the US Open, won her first match since losing the Wimbledon final.

The 37-year-old beat Belgian Elise Mertens 6-3 6-3 to reach the third round where she’ll face Russia’s Ekaterina Alexandrova who was a 6-4 6-3 winner over Zhang Shuai of China.

“Now that I’m just injury-free, I’m just enjoying being able to train, and I haven’t been able to do it since January, really,” Williams said.

“So I just think that the fact that I can train and practice and get in the gym is really going to be helpful for me.”

Mertens broke for a 2-1 lead but Williams answered in the sixth game to pull level at 3-3.

“I know when I got down one break I got real negative,” Williams said. “I don’t know what happened on the first time I got down. (She) just played really well. She’s obviously a really good player. I just needed to just double down and get more focused.”

Wimbledon champion Simona Halep survived a stern test from American qualifier Jennifer Brady with a 4-6 7-5 7-6 (7-5) victory to reach the last 16 and keep alive her hopes of a second consecutive title in Toronto.

Fourth seed Halep, who requested a medical timeout to get treatment on her left leg after the second set, clinched the two-hour 26-minute battle on her second match point when a Brady backhand caught the top of the net.

“She played great and ... she made a great match and was really difficult to play against,” Halep said in her on-court interview after her first career meeting with Brady.

Next up for Halep, who won the event last year in Montreal, will be the winner of Wednesday’s match between Croatia’s Donna Vekic and Russian wildcard Svetlana Kuznetsova.

— with AP