(Reuters) – Karolina Pliskova was left counting the cost of a performance well short of her best as she passed up a golden opportunity to push on for a maiden Grand Slam after losing to Anastasia Pavlyuchenkova in the Open third round on Saturday.

Russian Pavlyuchenkova secured her first career win in seven attempts over the world number two with the 7-6(4) 7-6(3) victory as the women’s draw saw another top 10 seed exit in the third round.

Defending champion Naomi Osaka and 23-times Grand Slam winner Serena Williams made third-round exits on Friday.

Sixth seed Belinda Bencic followed Pliskova out of the tournament on Saturday when she was thumped 6-0 6-1 by Anett Kontaveit.

Second seed Pliskova acknowledged that while the Russian had played well her own performance was nowhere near what she is capable of.

“She was playing very well today. Maybe the best what she played against me so far,” Pliskova said.

“But let’s say I was about 40% today of my game, so of course then she can feel so much better if I just don’t play (to the level) what I can play.”

Pliskova felt she was making mistakes that she would not normally make.

“I felt I did a lot of errors, actually. Maybe not huge errors, but I did a lot,” she said.

“And especially I think I was quite struggling with my serve, so the percentage was not there, not really many aces.

“I didn’t check the statistics yet, but I think I can serve much better.”

Czech Pliskova made 29 unforced errors to Pavlyuchenkova’s 43. She served six aces to the Russian’s five and only had a marginally worse first serve percentage.

Pavlyuchenkova, however, had five more break point than Pliskova, including six in a marathon second game of the match that lasted almost 18 .

The Czech fought off all but two of the 15 break opportunities Pavlyuchenkova had, which allowed her to force the match into tiebreaks.

Pavlyuchenkova, however, won the key points in both to clinch victory in two hours, 25 minutes.

“It hasn’t sunk in yet. I’m still in the match and on the next point,” Pavlyuchenkova said.

“I was thinking that if I take one or two games on her serve that would be because she is the ace queen on the tour so that was my , so I was focusing on returning well.

“I also managed to hold on my serve too, so that helped.”

She will next meet three-times Grand Slam champion Angelique Kerber in the fourth round after the German Italy’s Camila Giorgi 6-2 6-7(4) 6-3.

(Reporting by Greg Stutchbury in Wellington; Editing by Peter Rutherford)