PARIS (AP) Although Gisela Dulko missed the birth of her brother's twins because of the French Open, her sacrifice was rewarded Friday.

The 51st-ranked Argentine upset 2010 French Open finalist Sam Stosur 6-4, 1-6, 6-3 on center court to reach the fourth round and match her best result at the clay-court Grand Slam.

I stayed awake really late,'' said the 26-year-old Dulko, who became an aunt Thursday.It was very emotional, because I would have loved to be there (in Buenos Aires), but I'm here.''

Her brother, Alejandro, has a new son and daughter. After Dulko finished off Stosur on Court Philippe Chatrier, she brandished a towel reading in Spanish ``for Myla And Teo. It was worth it. I love them.''

Dulko had an up-and-down match against her eighth-seeded opponent.

After winning the first set, she let Stosur back in the match. But she made the decisive break in the sixth game of the third set.

Dulko, a former top-ranked doubles player, won her first title in almost three years this season in Acapulco to bring her career total to four. The win Friday was her first over a top-10 player at a major tournament.

Dulko reached a career-high ranking of No. 26 in November 2005. At majors, she also reached the fourth round at the 2006 French Open and the 2009 U.S. Open.

Up next for Dulko is No. 11 Marion Bartoli of France - with a quarterfinal spot on the line.

I feel comfortable and at ease,'' Dulko said.I expect something really tough in the fourth round. However, I don't think that this is too much pressure. I will do what I have always done so far. I will play my best tennis and enjoy it.''