France's Fiona Ferro broke serve to end both sets in a 7-5, 6-2 win over second-seeded Petra Martic of Croatia on Tuesday in the first round of the Tennis Championship Istanbul.
Ferro, a 24-year-old who is ranked 57th in the world, saved six of the eight break points she faced while converting half of her 10 break opportunities.
Top-seeded Elise Mertens of Belgium cruised in her opening match, downing Spain's Lara Arruabarrena 6-2, 6-0. Third-seeded Veronika Kudermetova of Russia edged the United States' Bernarda Pera 6-4, 3-6, 7-6 (4), taking control by winning four consecutive points in the decisive tiebreaker.
Fourth-seeded Daria Kasatkina of Russia and fifth-seeded Barbora Krejcikova of the Czech Republic advanced, but Anastasia Potapova topped sixth-seeded Anastasia Pavlyuchenkova 7-6 (2), 6-7 (8), 6-4 in an all-Russian showdown.
Porsche Tennis Grand Prix
Defending champion Petra Kvitova of the Czech Republic, the seventh seeded in the Stuttgart, Germany event, defeated the United States' Jennifer Brady 6-4, 6-3 in first-round action.
Kvitova won the tournament in 2019 before the 2020 edition was canceled due to the pandemic. The player Kvitova beat in the 2019 final, Estonia's Anett Kontaveit, also won her opener Tuesday, rolling past Germany's Julia Middendorf 6-2, 6-3.
Fifth-seeded Aryna Sabalenka of Belarus routed China's Shuai Zhang 6-2, 6-2. Russia's Ekaterina Alexandrova and Germans Anna-Lena Friedsam and Laura Siegemund also advanced.
--Field Level Media