(CNN) -- Former world number one Ana Ivanovic saved two match points before dispatching Roberta Vinci in three sets to reach the quarterfinals of the WTA event in Brisbane on Wednesday night.
Ana Ivanovic celebrates her victory over qualifier Roberta Vinci in Brisbane.
Top seed Ivanovic faced the match points while trailing a set and 4-5 but never looked back after bravely staving off defeat.
The Serbian proceeded to win nine of the last 10 games to secure a 6-7 7-5 6-1 victory to earn a quarterfinal clash with former world number one Amelie Mauresmo of France.
Ivanovic held the top ranking for three months in 2008 after winning the French Open before injury and loss of form saw her lose the status.
Mauresmo, herself beset by injury in recent seasons, had to survive a marathon three-and-a-quarter hour struggle against compatriot Julie Coin before winning 5-7 6-2 7-6.
She survived three match points after trailing 2-5 in the decider to eventually beat the world number 95. It was the longest match of Mauresmo's WTA career and she was almost lost for words after claiming the hard-fought victory.
"You know, I really don't know what to say about this match," Mauresmo was quoted on the official tournament Web site.
"I'm just glad that I won it because it would have really been the 'missed-occasions match' if I didn't. That's the good and positive point for today.
"Other than that it's a lot of ups and downs and frustration because I was not able to make the difference when I was supposed to and I had so many break points and was not able to convert them."
There was another marathon match in the women's last 16 as Italian Sara Errani beat Bulgarian Tsvetkana Pironkova 6-7 7-5 6-3 in more than three-and-a-half hours.
In the accompanying ATP tournament, second seed Jo-Wilfried Tsonga of France came back from a set down to beat Finn Jarkko Nieminen.
Tsonga lost the first set 6-0, but took the next two on tiebreakers to earn a quarterfinal clash with compatriot Richard Gasquet.
Spain's Fernando Verdasco also advanced with a straight sets win over Mario Ancic of Croatia, while Novak Djokovic's conqueror Ernests Gulbis went out. The Latvian was beaten 6-3 6-4 by Paul-Henri Mathieu of France in a second round match.
Mathieu will play Japan teenager Kei Nishikori, who beat fifth-seeded Czech Tomas Berdych 7-6 6-3 in the final match on Wednesday.