UPDATE 2-Tennis-Ivanovic made to battle hard in Brisbane

(adds Ivanovic quotes, later results)

SYDNEY, Jan 7 (Reuters) - French Open champion Ana Ivanovic survived two match points before sealing her place in the quarter-finals of the Brisbane International on Wednesday.

On a day when all the leading players were made to work overtime at the Australian Open warm-up tournament, Amelie Mauresmo and her French compatriot Jo-Wilfried Tsonga were also lucky to stay alive.

Top seed Ivanovic lost her opening set tiebreaker and was twice down match point in the second set but regained her composure to scramble past Italian qualifier Roberta Vinci 6-7 7-5 6-1.

Ivanovic said her mental strength allowed her to keep her title hopes on track.

"I went through a lot last year, both good and bad," the Serbian, runner up in Melbourne Park last January, told reporters.

"When you get through tough times it makes you stronger. That definitely happened to me... I definitely feel mentally tougher."

Next up for Ivanovic will be Mauresmo.

The former world number one spent more than three hours on court, including 89 minutes for the deciding third set, before beating fellow Frenchwoman Julie Coin 5-7 6-2 7-6.