Rome Masters: Four-time winner Serena Williams withdraws from tournament with a recurring knee problem

Rome: Serena Williams withdrew from the Italian Open on Tuesday with a recurring left knee injury.[caption id="attachment_6628051" align="alignleft" width="380"] File image of Serena Williams. AP[/caption]"Serena Williams has withdrawn with a new knee pain," organisers said.The 23-time Grand Slam champion's withdrawal comes a day after she beat Sweden's Rebecca Peterson in straight sets to set up a second round meeting with her older sister Venus.She had been returning after more than two months out with a knee problem, in the final warm-up clay-court tournament before the French Open.Four-time Rome winner Serena, 37, had eased through 6-4, 6-2 her first round match against Swedish qualifier Petersen.Serena had also played Petersen in the second round at the Miami Open in March before withdrawing with a knee injury.Her withdrawal sends Venus Williams, the 1999 winner, through to a third round meeting with either Johanna Konta of Britain or American seventh seed Sloane Stephens.