Serena Williams advances to Italian Open quarterfinals

ROME — Serena Williams overcame some frustrating moments in her 6-3, 6-3 win over 11th-seeded Shahar Peer in the third round of the Italian Open on Thursday.

After missing a series of backhands, including one that landed outside the doubles alley, Williams could be seen muttering to herself in dismay. Early in the second set, she slammed a ball that barely missed hitting a line judge, earning a warning from the chair umpire.

"I felt so bad. Thank God I didn't hit her," Williams said. "Obviously I was not going for the line judge. But that's what happens when you lose your temper, you can take someone out."

The incident occurred after Williams missed a first serve.

"I didn't serve well at all today," she said. "I don't think I got one first serve in during that game. But usually when I serve bad at the beginning of a tournament it gets better."

Neither player held serve until Williams took a 4-2 lead in the first set, as Peer's quickness matched Williams' power.

"It was definitely a good test. She plays a little like (Arantxa Sanchez-Vicario). She gets a lot of balls back," Williams said. "I knew she was going to be a tough opponent on clay. I thought I did pretty well."

Williams dropped her serve the first time she served for the match but closed it out the next time with a forehand winner up the line after a long rally.

Williams, who won the Australian Open in January to end a dry spell of two years without a major title, improved her season record to 18-2. Her next opponent will be 14th-seeded Patty Schnyder, who beat Samantha Stosur 6-4, 6-4.

Stosur upset top-seeded Amelie Mauresmo on Wednesday.

Third-seeded Jelena Jankovic dropped her serve three times in the second set, but held the first time she served for the match in beating Alona Bondarenko 6-4, 7-5.

Jankovic will next play Elena Dementieva, who advanced when fifth-seeded Nadia Petrova retired with a lower back injury.

After Dementieva broke to take a 4-3 lead in the first set, Petrova had a trainer come out to massage her back. Dementieva won the opening point in the next game before Petrova called it quits.

"I had an accident in the gym before the tournament," Petrova said. "It was getting better but then when I ran for a ball in the match today I felt a sharp pain."

The 10th-seeded Dementieva also reached the quarterfinals last year, losing to eventual runner-up Dinara Safina.

Also, ninth-seeded Daniela Hantuchova eliminated No. 7 Anna Chakvetadze 6-2, 6-3.

Second-seeded Svetlana Kuznetsova met lucky loser Yuliana Fedak later.