Frenchwoman Kristina Mladenovic upset top-seeded Garbine Muguruza of Spain 7-6- (4), 7-6 (6) to reach the quarterfinals of the Grand Prix SAR on Wednesday, while second-seeded Timea Bacsinszky of Switzerland reached the last eight with a hard-fought 7-6 (3), 6-3 win against Tatjana Maria.

With both players dropping serve five times, the 59th-ranked Mladenovic edged No. 20 Muguruza — the highest ranking player in the tournament — 5-4 in aces and next plays another Spaniard, Laura Arruabarrena.

Bacsinszky, who has had a breakthrough start to the year, struggled on her serve, but she also pressured her opponent's, breaking the German player five times. She improved to 25-3 and next faces seventh-seeded Slovakian, Anna Karolina Schmiedlova.

Fourth-seeded Elina Svitolina of Ukraine also advanced by beating American player Christina McHale 7-5, 6-3.