Rome, Italy – Serena Williams pulled out of her scheduled semifinal match against Li Na on Saturday at the Italian Open due to a lower back injury.
Williams entered Saturday on a 17-match winning streak after taking down Italian crowd favorite Flavia Pennetta in Friday's quarterfinals.
Fresh off her clay-court title in Madrid last week, Williams headed into Saturday's action with a 17-0 mark on clay this season.
The 2002 Rome champion, Williams' withdraw means that Li is through to the title match.
Li will appear in her second final of the year. She finished runner-up to Victoria Azarenka in Sydney.
Li will meet either reigning champion Maria Sharapova or German Angelique Kerber in Sunday's title match.
