Serena Williams credits improved serve for difficult second round victory in Paris

Seventh seed Serena Williams was forced to go the distance on Wednesday at Roland Garros, but eventually overcame Mihaela Buzarnescu to advance to the third round.

The American breezed through the first set, before facing some inspired play from her Romanian opponent. After dropping the second set, Williams regained control of the match, overcoming Buzarnescu in a 6-3 5-7 6-1 victory.

The 39-year old played some exceptional points, but credits her serve for seeing her through. She won 75% of points behind her first serve, and saved five of seven break points faced.

"I felt it was pretty good today," Williams said of her serve. "But I've been practicing my serve a lot. I've been playing in practice unbelievable on my serve. The other night was, wow. I'm glad it came better today.

"My coach told me it's good that I'm doing it well in practice because eventually it will be good in the match."

The 23-time Grand Slam champion will face compatriot Danielle Collins in the third round of the French Open, as the American cruised past Ukrainian qualifier Anhelina Kalinina in straight sets earlier in the day.