Paris, June 5 : Marketa Vondrousova of Czech Republic, who reached the 2019 French Open final, defeated Polona Hercog in straight sets, 6-3, 6-3, to enter fourth round of French Open late on Friday even as seeded players continued to fall at Roland Garros. Vondrousova, who had beaten four seeded players on way to final before losing to Ashleigh Barty in the 2019 edition, was superior to her opponent in every respect. She won 73 percent of first service points and converted three of the six break-points she got as against none by her opponent. The Czech player, who got a rousing reception in 2019 after the her achievement of entering final, hammered three aces. In another late third round game on Friday, Paula Badosa Gibert of Spain defeated Romania's Ana Bogdan in three sets. She won 2-6, 7-6, 6-4. Earlier, seventh-seeded American star Serena Williams kept her hopes of a 24th singles Grand Slam title alive as she overcame compatriot Danielle Collins 6-4, 6-4 to reach the fourth round. World No.32 Anastasia Pavlyuchenkova of Russia upset No.3 seed Belarusian Aryna Sabalenka 6-4, 2-6, 6-0 to reach the pre-quarterfinals for the second time. Aryna was the highest-ranked seed remaining in the tournament following the withdrawal of Japan's Naomi Osaka and the retirement of world No.1 Ashleigh Barty. After Aryna's loss, Americans No.4 seed Sofia Kenin and No.7 Serena Williams are the only top 10 player remaining in the bottom half of the draw. /IANS