Second-seeded Karolina Pliskova of the Czech Republic earned a straight-sets win in less than an hour over American Madison Brengle to move into the third round of the Miami Open, 6-1, 6-3, on Thursday.
Pliskova, who lost in the opening match in last year's tournament, was motivated to avoid a repeat.
"I just want to change this," she said. "I know I struggle after I do a good result in one tournament and then coming to a different tournament after.
"I think I'm in good shape this year, so hopefully I can change it in this tournament."
Pliskova finished with 27 winners and 30 unforced errors to Brengle's six and 24.
"The last few matches it's not really about my serve because the percentage is a little low, but I'm happy that I have my game from the baseline," Pliskova said. "I was feeling the ball pretty well today.
"It was a tough one today against an American, she has the home crowd supporting here. So I'm just happy to be through."
Fourth-seeded Dominika Cibulkova of Slovakia also advanced easily, 6-3, 6-2 over Veronica Cepede Royg of Paraguay.
"I just stayed aggressive," Cibulkova said. "It was my first match here, so it was pretty hot and it wasn't easy conditions. But I made it through. I'd never played her before, so that's always a new experience. I'm glad I got the job done."
Fifth-seeded Agnieszka Radwanska of Poland defeated Qiang Wang of China 7-6 (3), 6-1
"I had chances to take the first set earlier but it didn't end up the way I wanted," Radwanska told WTA Insider after the match. "I think the most important part of the first set was that tiebreak, which I played very well, very aggressive. I that was the key in the match."
In a group of upsets Thursday, American Bethanie Mattek-Sands topped ninth-seeded Elina Svitolina of the Ukraine 7-5, 6-4; Kirsten Flipkens of Belgium beat 29th seed Ana Konjuh of Croatia 7-6 (4), 6-7 (8), 6-2; Slovakian qualifier Jana Cepelova upset 18th-seeded American Coco Vandeweghe 6-2, 3-6, 6-1; and Czech Lucie Safarova topped 23rd-seeded Aussie Daria Gavrilova 6-2, 6-2.
Also Thursday, 26th-seeded Mirjana Lucic-Baroni of Croatia beat Ukrainian Kateryna Bondarenko 6-2, 2-6, 7-6 (2); 17th-seeded Russian Anastasia Pavlyuchenkova beat Yaroslava Shvedova of Kazakhstan 6-7 (3), 6-2, 6-0; 12th-seeded Dane Caroline Wozniacki topped American qualifier Varvara Lepchenko 6-1, 6-2; 30th seed Shuai Zhang of China beat Italian Sara Errani 4-6, 6-4, 7-5; and 27th-seeded Yulia Putintseva of Kazakhstan defeated Carina Witthoeft of Germany 6-4, 6-4.