Polish fifth seed Agnieszka Radwanska was the highest women’s casualty at the Miami Open on Saturday (Sunday AEDT), blown away for the second time this year by Croatian Mirjana Lucic-Baroni.

Radwanska had no answer to the 26th seed, who rolled to a 6-0 6-3 win in barely an hour.

“Today, I did a flawless job, a really beautiful performance. I’m proud of myself.” 35-year-old Lucic-Baroni told the WTA.

Lucic-Baroni also beat Radwanska at the Australian Open in January, in the second round en route to the semi-finals, where she eventually fell to Serena Williams.

“She was playing unbelievable tennis today,” Radwanska, speaking about Lucic-Baroni, told the WTA.

“She was very solid from the beginning, very aggressive, hitting everything with unbelievable speed. I couldn’t do much.”

Another high seed had a fright, No.6 Garbine Muguruza overcoming a slow start to beat China’s Zhang Shuai 4-6 6-2-6-2 in over two hours.

“Since I’ve started the year, I’ve had a lot of matches like this, and I’m expecting that every time I go on court,” Muguruza said.

“A win is a win, I don’t wish to have matches this tough every day, but I’m very happy with the way I’m facing them.”

Second seed Karolina Pliskova’s match went according to form, the Czech beating Kazakhstan’s Yulia Putintseva 7-5 6-3 while Australian Daria Gavrilova’s first-round conqueror Lucie Safarova was far too good for Croatian wildcard Ajla Tomljanovic 6-1 6-3.

Slovakian Dominika Cibulkova, the fourth seed, cruised past Kirsten Flipkens 6-2 6-3 while former world No.1 Caroline Wozniacki had little trouble defeating Sorana Cirstea 6-4 6-2.

Czech Barbora Strycova, the 15th seed, accounted for Jana Cepelova 6-2 6-4 but the 17th seed, Anastasia Pavlyuchenkova, was sent packing, beaten 4-6 6-0 6-3 by American Bethanie Mattek-Sands.