Rome: American Serena Williams reached the third round of the Rome Open tennis after being pushed to dig deep to beat Russia's Nadia Petrova.

Ninth-seeded Williams lost her last two meetings with Petrova, as well as two of their three previous clay court meetings, and an upset loomed as the big-serving Russian won the first set 6-4 and held triple break point at 1-all in the second set.

However, Williams came back swinging, saving five break points in that game and never looked in danger again, eventually winning 4-6, 6-2, 6-3.

"When I lost the first set, I just thought, 'Stay in there and just don't give up, you'll have a chance'," Williams was quoted as saying by Xinhua. "I just didn't want to give up. I never do want to give up, nor have I ever wanted to give up."

Williams is now 15-0 on clay this season, going 5-0 to win Charleston, 2-0 in Fed Cup play, 6-0 to win Madrid and 2-0 so far here. The last time anyone pulled off a perfect clay court season was Justine Henin's 24-0 run in 2005.

"I love Europe and to be able to play the whole season here is really cool," Williams said. "I've definitely developed a lot of confidence on clay. I like it a lot. Well, I've always liked it. It's just that I haven't won a lot of tournaments on it, but now I'm getting more wins and hope to change that going forward."

The 13-time Grand Slam champion continued to describe her passion for the sport. "I am so inspired to be out there," she said. "The only incentive I have is that I love tennis and I love playing. There are a lot of times in life you don't get the chance to do what you do best, but this is definitely where I belong."

Next up for Williams is Anabel Medina Garrigues. Curiously, the two veterans - Williams 30, Medina Garrigues 29 - will be playing against each other for the first time.

Venus Williams also moved through to the third round, battling back from 3-5 down and needing six set points to close out the first set but then rolling past Ekaterina Makarova for a 7-6(7), 6-1 victory.

Next up for Williams is No.5 seed Samantha Stosur. Williams leads the overall head-to-head 4-1 but Stosur won their only 2012 meeting.

In the night match, No.1 seed Victoria Azarenka beat Shahar Peer 6-1, 6-2, never facing a break point and winning nearly twice as many points in the match (57 to 29).

Azarenka withdrew from the tournament afterwards with a shoulder injury. (IANS)