World number two Petra Kvitova shrugged off the embarrassment of one of the worst missed shot of the tournament to advance to the quarter-finals of the Australian Open with a 6-2 7-6 victory over former world number one Ana Ivanovic.

The 21-year-old Wimbledon champion was lining up her second successive smash to win the point in the ninth game of the second set but totally mistimed the shot and the ball bounced off her arm to gift Ivanovic the game.

The world number two shrugged off the embarrassment of what may have been the worst shot of her career.

"I know that it looked really strange when I missed it," said the 21-year-old. "But anyway ... I won, that's the important thing."

Kvitova, perhaps mindful that footage of the shot will shortly become an Internet hit, temporarily lost her composure and dropped her serve for the first time in the match.

Ivanovic, who made the final at Melbourne Park and then won the French Open in 2008, held to take a 6-5 lead but the Czech then held serve to force a tie-break that she raced through.

She now faces a last eight match against Italy's Sara Errani who beat China's Zheng Jie 6-2 6-1 to reach her first Grand Slam quarter-final.

Kvitova's role model Martina Navratilova said the fact that she did not fall apart completely after the clanger showed that she could cement her place as one of the top women in the world.

"Today she hit a whiff on the overhead, embarrassed as heck," Navratilova said. "Shanked like six balls in a row, but got it together, held serve. In years past, and even last year, she would lose those matches or lose her concentration.

"But now she gets it back together. She's tough. I'm glad I'm not the on the other side of the net.

"With the absence of Serena (Williams) playing enough, we need some superstars that you really feel like they're holding their own. I think Petra has that possibility."

Kvitova says she is flattered to be compared with Navartilova, who won 18 Grand Slam singles titles.

"She is a legend. She won many grand slams and was originally from the Czech Republic. She was my idol growing up and it's nice to have that (comparison)," she added.

"I don't think it adds any pressure. It's a nice thing to have."

Kvitova, who could take Caroline Wozniacki's world number one ranking at the year's first grand slam, also looked forward to playing in London at the Olympic Games.

"I really want to play in the Olympics and play at Wimbledon on the grass, where I won last year. I really want to represent my country and be with the other athletes.

"It will be really enjoyable."

Reuters