Reigning champion Maria Sharapova and Li Na of China will meet in Sunday's title match at the $2.168 million Italian Open tennis event, a clay-court French Open tune-up.
Li advanced to her second final of the year without having to play a match on Saturday, as American Serena Williams withdrew prior to their scheduled semifinal match 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 also headed into Saturday's action with a 17-0 mark on clay this season.
"Everyone. I'm soooo sad and sorry I had to pull out of what has become my favorite tournament in Rome," Williams said on her Twitter account. "Everyone has become so nice here in Rome and the tournament Director is amazing. I will be here next year for sure."
Williams said that she will be ready for the French Open, which is just eight days away.
"I feel fine. This is a good week to get better and I'm confident that I'll be 100 percent," Williams said. "It's just life and playing a lot and the body is just getting used to playing a lot of matches and that's all."
The 2002 Rome champion, Williams' withdraw means that Li is through to her first final since finishing runner-up to Victoria Azarenka in Sydney.
Li will do battle with Sharapova in Sunday's title match.
The second-seeded Russian beat German Angelique Kerber, the No. 12 seed, 6-3, 6-4 to reach her fourth final of 2012.
The three-time Grand Slam champion Sharapova beat reigning U.S. Open champ Sam Stosur in last year's finale in Rome.
"Coming back to a place where you have accomplished so much, and to be in a position to regain that success, makes me very happy," Sharapova said. "It was a tough match today and I'm looking forward to another tough one tomorrow."
Sharapova is 6-4 lifetime against Li.
The 2012 Rome titlist will collect $385,000.