Sharapova ends Venus' run, Serena reaches semis

ROME (Reuters) - Holder Maria Sharapova ended the encouraging run of Venus Williams to reach the semi-finals of the Italian Open on Friday, while Serena Williams enjoyed an easy passage through to the last four.

World number two Sharapova downed Venus 6-4 6-3 in a high-quality encounter to set up a clash with either Wimbledon champion Petra Kvitova or Germany's Angelique Kerber.

Serena was leading Flavia Pennetta 4-0, 40-0 when the Italian retired with a right wrist injury. She will play China's Li Na who beatDominika Cibulkova 6-1 7-6.

A break of serve at 4-4 in the first set proved to be the key for Sharapova as she served out and then moved ahead early in the second.

Venus got the break back but immediately handed Sharapova the advantage once more and this time the second seed held on to reach her fifth semi-final of the year.

However, Venus will be reassured by a rise in her ranking that should ensure she is included in the United States team for the London Olympics.

The American only returned to the tour in March after six months out having been diagnosed with Sjogren's syndrome, which saps her energy.

For Serena, the extra time off was a relief after a hectic schedule during which she has won titles on clay in both Charleston and Madrid.

"It's never nice to go through like that but it is nice to have kind of a semi-day off," Serena said.

"I've been playing every day for I don't know how many days so it definitely helps."

Serena had almost a year off because of a blood clot in one of her lungs, returning to the tour just before Wimbledon.

The world number six said she was now feeling more confident than last summer, when she won back-to-back tournaments before losing in the final at the U.S. Open.

"I definitely feel better because I've played more tournaments," she said. "Last summer my lungs had not recovered completely."

Serena said she expected a tough match against Li, whom she has never played on clay.

"Li's the defending French Open champion and a great all-court player so it's going to be a really good test for me."

Li let slip a 5-2 lead in the second set before beating Cibulkova, taking the second-set tiebreak 7-4.

(Editing by Pritha Sarkar and Alison Wildey)