Chinese No 1 Li Na reached the French Open second round after edging French 17-year-old Kristina Mladenovic 7-5, 6-3 on Monday but said it had been her worst performance of the year.

Chinese No 1 Li Na reached the French Open second round after edging French 17-year-old Kristina Mladenovic 7-5, 6-3 on Monday but said it had been her worst performance of the year.

Mladenovic, the reigning junior champion and the youngest player in the draw, held her own throughout a competitive match but world No 12 Li eventually prevailed in one hour and 39 minutes.

Li went into the match on the back of some impressive clay performances, culminating in a semifinal showing at Warsaw last week and declared herself disappointed by her performance against Mladenovic.

"Today was the worst I played all season," she said."I was nervous in this match. In the first match everyone is nervous but also she was French so the whole crowd was for her and I didn't play at my level. I felt like I played like a junior."

Li, who reached the Australian Open semifinals earlier this year, will face French wildcard Stephanie Cohen-Aloro in the next round.

"I was feeling really good before this match," Li said. "After the match I said to my coach: 'What am I doing on the court?' I wasn't playing like a top 20 player. I just want to forget this match and look forward to the second round."

The Chinese broke her opponent's serve first but Mladenovic broke back immediately and when Li handed her a chance to go a break up in the seventh game, she seized it with a pinpoint backhand return across the court.

Li, the 11th seed, levelled things straight away by breaking back in the next game though and took a one-set lead when the stretching teenager slammed an attempted forehand into the ground at 5-6 and 15-40 down.

The players exchanged breaks early in the second set before Li hit back from 15-40 down in the sixth game to secure the decisive break and then fought off three break points in the final game to book her place in round two.