Justine Henin opened the defence of her French Open crown with a battling 6-4 6-3 win over 20-year-old Russian Elena Vesnina on Sunday.
After a wait of nearly six hours because of rain, the world number one, who won the title in 2003, 2005 and 2006, came from 3-1 down in the second set to clinch victory and set up a clash with Austrian Tamira Paszek.
"I think she played a very good match but at the end I decided to be a tougher player. Winning's all that matters today," said Henin.
The Belgian was broken when serving for the first set at 5-3 but the lapse was only temporary as she broke in the next game to clinch the set.
Vesnina, the world number 65, showed her potential as she broke on her way to a 3-1 lead in the second set but Henin then reeled off five consecutive games to advance to round two.
The long wait to get on to court had been tough to deal with, Henin said.
"I almost panicked when (Marat) Safin finished and the covers were still off," she said. "Then when we played, it was very difficult. It was very damp and humid, almost like stormy conditions."
Henin said she expected a tough match against Paszek, having needed three sets to beat her in the second round of the WTA event in Dubai earlier this year.
Henin said of her Austrian opponent: "She is a real fighter, a young player coming pretty strong on the tour. I have to be very careful and to try to play better and better as I go on."
Henin is bidding to become the first woman since Monica Seles in 1992 - and only the second in the professional era - to win the title in three successive years.
