Montreal, Aug 13 (IANS): Tunisia's Ons Jabuer won eight of the last nine games from 4-4 in the second set to seal a quarterfinals berth in the National Bank Open with a 6-7(5), 6-4, 6-1 over defending champion and world No. 8 Bianca Andreescu of Canada.

Bianca battled gamely through an injury scare late in the second set -- the Canadian landed awkwardly on her left foot, but was able to continue the match after receiving a medical timeout -- before losing the match in 2 hours and 39 minute.

"I wanted to move her to see what kind of pain she was feeling. I was trying to make her move a lot to see if it's really affecting her," Ons said after the match.

"I think she got tired a little bit. I can see that from the second set. It's completely normal. Honestly, I didn't focus a lot of what she was having. I was more focusing on myself, of what I should do. I really focused on returning better, serving better. It helped me a lot in the third set."

Nonetheless, that proved a turning point for the Tunisian, who employed her deft drop shots to overpower her opponent.

"[It was a] great match. It was a tough one. I know coming to play Bianca here in Montreal, in Canada, was going to be difficult," Ons said. "But I think I played good tennis. I had my opportunities in the first set. But I'm glad that I did good in the second and third set and I didn't let the rain, the injuries, stopping all the time, make me lose my focus. I'm pretty happy with the way I stayed mentally and physically very ready."

In other matches on Thursday evening, No.4 seed Karolina Pliskova of the Czech Republic moved into the quarterfinals defeated Amanda Anisimova of the US 6-1, 7-6(10), while compatriot, No.7 seed Petra Kvitova, was upset on the in the round of 16.

Italy's Camila Giorgi was the player to take out Petra, as the world No.71 dispatched the 2012 champion 6-4, 6-4, in an hour and 36 minutes.