BASTAD, Sweden (AP) Top-ranked Serena Williams sailed through her opening match at the Swedish Open with a 6-2, 6-1 win over Belgian qualifier Ysaline Bonaventure in the first round on Wednesday.

Four days after winning her sixth Wimbledon title, Williams ousted Bonaventure from the clay-court tournament in 53 minutes despite a first-serve percentage of 64.

Williams, the 2013 Bastad champion, next faces Czech player Klara Koukalova, who beat the American on clay six years ago.

Seventh-seeded Johanna Larsson of Sweden advanced to the second round after beating Richel Hogenkamp of the Netherlands 6-1, 6-3 and will play Anna-Lena Friedsam of Germany.

In the first three second round matches, Lara Arruabarrena of Spain rallied to upset second-seeded Samantha Stosur of Australia 7-6 (5), 6-0, after being 2-4 down in the first set.

Fourth-seeded Mona Barthel and Jana Cepelova joined Arruabarrena in the quarterfinals.

Germany's Barthel crushed Maryna Zanevska 6-0, 6-0 while Slovakia's Cepelova came from a set down to beat Olga Govortsova 4-6, 6-3, 6-2.