Eleventh seed Tatiana Golovin of France had to retire with a hamstring problem after losing the first set 7-5 to Thailand's Tamarine Tanasugarn and No. 12 Li Na of China withdrew with a rib injury.

Safarova made a rocky start against Russian Poutchkova, falling 2-5 behind in the first set, but quickly got used to the conditions on the quick hard courts.

"I forgot my confidence back and began to serve well and I was coming inside the court and being more aggressive," Safarova told reporters.

The 20-year-old Czech has had a fine season, reaching the Australian Open quarter-finals, the Paris Indoors final and the French Open fourth round.

Golovin only returned to the tour at Wimbledon after taking two and half months off due to an ankle injury.

"I didn't want to risk a big injury so I decided to stop," Golovin said. "I played like six matches in three days. Hopefully I can play Toronto next week, because I need some more matches."

Tanasugarn next faces Gisela Dulko of Argentina, who beat Sun Tiantian of China 7-5 6-4.

Thirteenth seed Sybille Bammer of Austria also advanced, beating American Laura Granville 6-4 6-2, while Ukraine's Yuliana Fedak upset compatriot and 14th seed Alona Bondarenko 1-6 6-2 6-3.

American Ashley Harkleroad overcame Jamea Jackson in straight sets and next faces third seed Ana Ivanovic of Serbia, who is playing her first tournament since Wimbledon.

San Diego champion Maria Sharapova, the top seed, plays her first match on Wednesday