Two-time defending champion Serena Williams withdrew from the Madrid Open on Friday because of a left thigh injury. Williams' decision gives Petra Kvitova a walkover into the semifinals.
'It started to get better but, most importantly right now, I just need some time to rest and recover," Williams said in a statement. "It's beyond words. It's so frustrating. This is not the way I wanted this week to end."
Despite multiple reports that Williams would miss next week's Italian Open, the world No. 1 remains in the field for now.
"I am planning to play Rome," she said, according to Neil Harman, who is in Madrid for the London Times. "I have a bye so have an extra day of rest. I will take it one day at a time."
Williams also tweeted that she's "recovering fast and getting ready for Rome and Roland Garros," where she is the reigning champion at both tournaments. The French Open begins on May 25. Both times she has won the Italian Open, in 2013 and 2002, she has gone on to win her two French Open titles.
Williams went 28-0 on clay last year, including 23-0 through the French Open. This year, however, she lost her opening match at the Family Circle Cup last month and now is dealing with an injury after winning three matches in Madrid.