ROME, May 17 (UPI) -- Maria Sharapova missed her scheduled semifinal match at the $1.34 million Italian Open in Rome Saturday because of a strained left calf.

The event's second seed was to face defending champion and fourth-seeded Jelena Jankovic of Serbia.

"I think it was in the beginning of the second set yesterday, I started to feel it," Sharapova told reporters.

On Friday, the Russian needed nearly three hours to beat No. 9 seed Patty Schnyder of Switzerland 6-7 (3-7), 7-5, 6-2 in a quarterfinal match.

Sharapova joined fifth-seeded Serena Williams (back) on the sidelines in the past two days with an injury.