LOS ANGELES, Nov 11: Serena Williams rallied to beat fellow American Jennifer Capriati 2-6 6-4 6-4 Sunday to reach the final of the $3 million WTA Championships, but the world number one will not be joined by her sister Venus.

Three times this season, at Wimbledon, the French and U.S. Opens, Serena and Venus have clashed for titles.

But defending champion Serena stepped on to the Staples Center court knowing the prospects of another all-Williams showdown had disappeared after Venus retired from her semifinal with Belgian Kim Clijsters earlier in the day because of a leg injury.

Serena, who has lost just four matches this season, appeared to be ready to join her older sister at the exit door when third seed Capriati, hunting her first title since the Australian Open, surged into a 3-0 lead on the way to claiming the first set.

Playing in her first event since lifting her season-leading eighth title five weeks ago, Serena struggled to find her range, committing a massive 53 unforced errors.

But she found her shots when she needed them most, breaking Capriati to take the second set and level the match.

The largest crowd of the week at the Staples Center was then treated to a riveting third set, the two players stepping up their games as the pressure mounted.

Once again Capriati took the initiative, breaking Williams to go in front 2-1, pumping her fist as she sprinted to her chair for the changeover.

But Williams broke back to level the contest at 3-3 and again to close out the match.

It was the 11th meeting between the two rivals, Serena winning seven, including all five When Venus appeared on court with her left calf and ankle heavily strapped, it quickly became apparent the world number two was in distress and an all-Williams final in doubt as fifth seed Clijsters surged into a 5-0 lead.

During the changeover Williams limped to her chair calling for the trainer, and after a brief discussion stood up and walked over to Clijsters, telling the Belgian she could not continue.

It was only the second time in her career that the durable Williams had retired from a match due to injury.

Sunday’s results: