Write a question about the following article: Petrova was ranked world No. 76 going into the 2003 French Open. In the first round she beat the three-time champion and world No. 12 Monica Seles 6-4, 6-0, on what was to be Seles last professional match. She then defeated Silvija Talaja 6-1, 6-1 and Marissa Irvin 6-1, 6-1 to reach the fourth round. Here, Petrova stunned 7th seed Jennifer Capriati 6-3, 4-6, 6-3. In the quarterfinals, Petrova won again in three sets over 21st seed Vera Zvonareva 6-1, 4-6, 6-3 to reach her first ever Grand Slam semifinal. Petrova faced world No. 2, Kim Clijsters, and despite having a set point in the first set, Petrova was beaton in straight sets 7-5, 6-1. Despite this, Petrovas ranking increased to world No. 30.

Question about the article:
How many sets did Petrova win against Monica Seles in round one?