Top-seeded Venus Williams advanced to the quarterfinals at the inaugural WTA Brasil Tennis Cup, though it took a tougher-than-expected victory over Garbine Muguruza on Wednesday for the seven-time Grand Slam champion to move on.
Williams was taken to the limit by the 19-year-old Muguruza, ranked 96th in the world, before ultimately prevailing by a 6-4, 2-6, 7-5 score on the hardcourts at Federacao Catarinense de Tenis.
Muguruza staved off three match points while serving to tie the match at 5-5 in the final set, but Williams was able to hold serve before breaking the young Spaniard to prevail in a two-hour, 12-minute marathon.
Williams' next opponent will be Magdalena Rybarikova, with the fifth-seeded Slovak holding off Spanish qualifier Beatriz Garcia Vidagany 6-4, 3-6, 6-4 in her second-round bout.
In other second-round action involving seeds, Hungarian Timea Babos upset No. 4 Chanelle Scheepers of South Africa 6-1, 6-2 and No. 7 Kristina Mladenovic of France whipped German Tatjana Malek 6-2, 6-1.
Additionally, Hungarian Melinda Czink overcame Brazilian wild card Beatriz Haddad Maia 1-6, 6-2, 7-6 (7-3), Russian Olga Puchkova came back to beat France's Caroline Garcia 3-6, 6-3, 6-3, and Romanian Monica Niculescu mauled Croatian qualifier Tereza Mrdeza 6-1, 6-1. Czink will encounter Mladenovic, while Puchkova will face Czech Jana Cepelova and Niculescu will battle Babos in the round of eight.