Sixth-seeded Garbine Muguruza of Spain won 80 percent of her first-serve points en route to taking down Sorana Cicirc;rstea of Romania 6-3, 6-2, in the first round of the Bett1Open in Berlin on Tuesday.
No. 7 seed Victoria Azarenka, a former World No. 1 like Muguruza, also advanced Tuesday with a 6-4, 7-6 (2) victory over Germany's Andrea Petkovic. The Belarusian star will face German Angelique Kerber in the next round after Kerber dispatched Misaki Doi of Japan 6-2, 6-1, in one hour flat.
In other action, Veronika Kudermetova of Russia upset No. 8 Karolina Muchova from the Czech Republic, 7-6 (5), 5-7, 6-2. Other winners included Russia's Liudmila Samsonova, Croatia's Petra Martic, Kazakhstan's Elena Rybakina and Jessica Pegula of the United States. Pegyula advanced after American Hailey Baptiste retired late in the first set.
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In a match that required tiebreakers in all three sets and lasted three hours and nine minutes, Ajla Tomljanovic of Australia took down top-seeded Elise Mertens of Beligum, 7-6 (5), 6-7 (5), 7-6 (4) in Birmingham, England.
Neither player broke serve in the third set until the tiebreaker, as Tomljanovic jumped ahead 5-2 and held on from there. Tomljanovic overcame Mertens' 14 aces to win, although the No. 1 seed also had 12 double-faults.
Other winners Tuesday included No. 2 seed Ons Jabeur of Tunisia, No. 4 seed Daria Kasatkina of Russia, No. 5 seed Jelena Ostapenko of Latvia, No. 6 seed Shuai Zhang of China, Leylah Fernandez of Canada, Marta Kostyuk of Ukraine and Anastasia Potapova of Russia.
--Field Level Media