LOS ANGELES (TICKER) -- A promising tournament ended in disappointment for Maria Sharapova.
The top seed at the East West Bank Classic was forced to withdraw from her semifinal match with No. 4 Nadia Petrova on Saturday due to muscle tightness in her lower left leg.
The beneficiary of the walkover victory, Petrova moved into Sunday's final to face No. 3 Ana Ivanovic, a 4-6, 6-3, 7-5 winner over No. 2 Jelena Jankovic earlier in the day.
"This afternoon, I started feeling my muscle was getting tighter and tighter when I came here," Sharapova said. "When I started to warm up, it was getting worse and worse. It has happened very fast in the last couple of hours. ... It's just so weird how it came on."
A winner at San Diego last week, Sharapova said she endured a battery of treatments in an effort to get on the court.
"I had it all, deep tissue, ice bath, I even had acupuncture in my ear," she said. "I have done it all in the last two hours."
The 20-year-old Russian would not speculate about whether she will be healthy enough to defend her U.S. Open title later this month.
"Like I said, based on my experience, you never know, but I hope it is only a couple of days," she said.
A fellow Russian, Petrova said it is "good" to be in the final of the $600,000 hardcourt event but is disappointed Sharapova was unable to compete.
"I had a lot of people coming to watch me and support me, I was actually looking forward to tonight's match," she said.
Petrova was coming off a 6-7 (3-7), 6-4, 6-1 victory over unseeded Frenchwoman Virginie Razzano in the quarterfinals. Seeking her eighth career title, this will be her first final in six appearances here.
Petrova's finals opponent, Ivanovic owns a 3-2 edge in the all-time series and has won both hardcourt matches between the players.
Seeking her fourth career title and second this season, Ivanovic found her path to finals far more difficult.
Things appeared bleak for the stunning 19-year-old in the third set, when she fell behind, 4-1, against the world's third-ranked player. However, Ivanovic broke her compatriot to get to 4-3 before holding serve and evening the match.
Jankovic grabbed a 5-4 advantage but failed to win another game as Ivanovic held serve and earned one of her five break points before serving out the match.
Ivanovic's perseverance was evident in the fact that she saved 17-of-21 break points during the match, which lasted 2 hours, 28 minutes.
The loss was another frustrating chapter in Jankovic's recent history with Ivanovic, who has won four consecutive matches in the series - including all three meetings this season. The only win for Jankovic in six matchups with her countrywoman took place here in the quarterfinals last year.
First prize is $88,260.