MADRID -- Sara Errani of Italy beat Andrea Petkovic 7-5, 6-1 in the first round of the Madrid Open on Saturday, avenging a loss to the German in the same stage four years ago.

Errani advanced to play countrywoman Francesca Schiavone or Russia's Elena Vesnina.

Errani placed 87 percent of her first serves in, and broke Petkovic five times while saving five of six break chances against her.

Also, Bojana Jovanovski of Serbia beat Karin Knapp of Italy 6-1, 6-1, while American Alison Riske outlasted Estonia's Kaia Kanepi 6-7 (7), 6-1, 6-2.

Christina McHale bettered training partner and fellow American Lauren Davis 7-6 (2), 6-3.

Other winners from the first round included Spaniards Garbine Muguruza and Lara Arruabarrena, and Magdalena Rybarikova of Slovakia.