Second seed Petra Kvitova ended Ana Ivanovic's charge through the Australian Open field with a 6-2 7-6 (7-2) victory.
Wimbledon champion sees off Ivanovic's fightback
Second seed Petra Kvitova ended Ana Ivanovic's charge through the Australian Open field with a 6-2 7-6 (7-2) victory.
Ivanovic had been bidding to reach her first grand slam quarter-final in three-and-a-half years - with the Serb having shown signs at Melbourne Park that she was back to her best.
However the former world No.1, the French Open champion in 2008, had no answer for the power and guile of Kvitova.
The Czech had looked on course for a straightforward victory as she broke Ivanovic twice in the first set.
Another break for the Wimbledon champion followed in the second set before Ivanovic rallied - with Kvitova losing her way after taking an airshot at a simple smash in the ninth game.
Tough
Ivanovic broke to love when Kvitova was serving for the match and then held in impressive fashion to force the tie-break.
Kvitova, though, regained her composure to seal the win - with Ivanovic's serve letting her down when it mattered the most.
She delivered two double faults to slip 3-1 down and Kvitova prevented a comeback to advance to the last eight.
"It was a tough match, especially at the end," Kvitova said. "I lost eight points in a row but I was happy with how I played in the tie-break."
Ivanovic added: "She is a tough opponent.
"You really have to try to get a swing on the ball and hope you get some rhythm and that's going to cause some errors. That's what happened to me today.
"But it has been a nice tournament for me, I played some really good tennis and proved to myself that I can play at that level and compete against the best."
Kvitova will now take on Sara Errani after the 24-year-old Italian toppled Jie Zheng.
Errani was in total control on Margaret Court Arena as she rattled off a 6-2 6-1 victory against the two-time grand slam semi-finalist.
