Australian Open champion Caroline Wozniacki made a winning start to the clay season as she breezed past Ekaterina Alexandrova 6-2 6-2 at the Istanbul Cup.

The Dane converted five of six break point opportunities to win in 68 minutes and advance to a second-round clash with Sara Errani or Kirsten Flipkens.

"It was tricky, for sure," she said. "The first match on clay is never easy, but I'm happy with the win.

"It's great just to get a match in, and feel better with the movement. It's all about fine-tuning in matches like these.

"I'm using this as a preparation for the next few weeks, because the French Open is obviously around the corner.

"There's lots to look forward to, and I want to keep feeling like I'm getting into the groove on clay."

It was not such a good day for third seed and 2008 champion Agnieszka Radwanska, who had to retire with a back problem at 6-1 2-0 down to Donna Vekic.

Seeds Zhang Shuai and Sorana Cirstea also suffered first-round exits to Arantxa Rus and Yulia Putintseva respectively, while Irina-Camelia Begu won the last 11 games of her 7-5 6-0 victory against qualifier Dalila Jakupovic.