Marrakech, Morocco (SportsNetwork.com) - Top seed Garbine Muguruza of Spain went by way of an upset Wednesday at the Moroccan Grand Prix tennis event.

France's Kristina Mladenovic took out Muguruza in a pair of tiebreaks, 7-6 (7-4), 7-6 (7-6), at this clay-court tournament.

Three other top-four seeds reached the quarterfinals in Marrakech, as No. 2 Timea Bacsinszky of Switzerland held off German Tatjana Maria 7-6 (7-3), 6-3, No. 3 Flavia Pennetta of Italy overcame German qualifier Laura Siegemund 4-6, 6-1, 6-3 and No. 4 Elina Svitolina of Ukraine dismissed American Christina McHale 7-5, 6-3.

In other second-round action involving seeds, Italian Karin Knapp took out No. 6 fellow countrywoman Roberta Vinci 6-7 (3-7), 6-2, 6-2, No. 7 Slovak Anna Karolina Schmiedlova came back to beat Argentine qualifier Maria Irigoyen 3-6, 6-1, 6-3 and Spaniard Lara Arruabarrena upset No. 8 Monica Puig of Puerto Rico 7-5, 6-2.

One other Day-3 result saw Hungarian Timea Babos sneak past qualifier and recent Bogota champion Teliana Pereira of Brazil 6-0, 6-7 (5-7), 6-4.

Thursday's quarterfinals will pit Bacsinszky against Schmiedlova; Pennetta versus Babos; Svitolina against Knapp; and Mladenovic versus Arruabarrena.