Serena Williams was untroubled in her Western and Southern Open curtain-raiser, while Victoria Azarenka’s stranglehold on Caroline Wozniacki continued on Wednesday.
Top seed Williams accounted for Tsvetana Pironkova 7-5 6-3 – the former’s title defence in Cincinnati starting without a hitch.
Williams sent down 15 aces in 11 service games, saving all three break points she faced – and she got the crucial break of Pironkova’s serve late in each set to progress in one hour, 29 minutes.
Meanwhile, Azarenka’s recent spell on Wozniacki continued – the Belarusian posting a 6-0 6-4 victory.
It was the sixth consecutive two-set win for Azarenka over fellow former number one Wozniacki, who conceded a 6-0 set for the first time since the London Olympics in 2012.
Fifth seed Wozniacki was joined in making an early exit by Petra Kvitova, the fourth-seeded Czech bowing out to Caroline Garcia 7-5 4-6 6-2.
The result marked Garcia’s highest-ranked scalp in her WTA Tour career – Kvitova is ranked fourth – and continued the two-time Wimbledon winner’s on-court struggles since revealing she was battling mononucleosis.
All other seeds were safely through to the third round, including Simona Halep (3), Lucie Safarova (7), Karolina Pliskova (8), Elina Svitolina (14) and Andrea Petkovic (15).
Halep was forced to work for her 7-5 5-7 6-4 win over Kristina Mladenovic, while Safarova also won a tight encounter 6-4 7-5 over wildcard Coco Vandeweghe.
Pliskova also had a 6-4 7-5 win, knocking off qualifier Timea Babos, while Svitolina edged out Eugenie Bouchard 7-6 (8-6) 7-5 and Petkovic fought back to beat Camila Giorgi 5-7 6-3 6-3.
Rogers Cup champion Belinda Bencic showed no signs of letting up, the Swiss thrashing Flavia Pennetta 6-1 6-4.
Americans Sloane Stephens and Varvara Lepchenko continued their runs at the WTA Premier hard-court event.
Stephens eventually got past qualifier Mona Barthel 3-6 7-6 (7-1) 6-2, and Lepchenko saw off lucky loser Mirjana Lucic-Baroni 7-5 6-4.
Lepchenko, originally meant to play Maria Sharapova in the second round before the Russian’s withdrawal to injury, now has a big chance to reach the quarter-finals, as she takes on qualifier Anna Schmiedlova next.
Schmiedlova defeated Irina-Camelia Begu 6-1 6-3.
Anastasia Pavlyuchenkova came back to beat qualifier Yaroslava Shvedova 2-6 6-3 6-2, while Jelena Jankovic was too tough for Madison Keys 7-6 (7-4) 6-4.
Karin Knapp awaits Williams in the third round, after the Italian comfortably accounted for Daria Gavrilova 6-4 6-1.