Serena Williams has withdrawn from the Italian Open with left knee pain but is confident of being fit for the French Open.
The 23-time grand slam singles champion had been due to face sister Venus for the 31st time after beating Rebecca Peterson in the first round on Monday.
Williams said on wtatennis.com: "I must withdraw from the Italian Open due to pain in my left knee. I will miss the fans and competition at one of my favourite tournaments.
"I'll be concentrating on rehab and look forward to seeing you all at the French Open and next year in Rome."
