American sisters Venus and Serena Williams will face off Saturday, for the sixth time in a grand-slam tennis final, as the play once again for the Wimbledon championship.

The 21-year-old defending champion, Serena, is a heavy favorite over her 23-year-old sibling, Venus, who continues to suffer from an abdominal strain picked up in April.

Venus, Serena Williams Face Off at Wimbledon Women's Finals - 2003-07-05

World-number-one Serena practiced on Friday, while fourth-seed Venus rested.

Venus, Serena Williams Face Off at Wimbledon Women's Finals - 2003-07-05

Despite the injury, Venus says she will be on the court for her fourth straight Wimbledon final. Venus won the title in 2000 and 2001, and is 26-1 at Wimbledon in the past four years. She has a total of four grand-slam titles.

Venus, Serena Williams Face Off at Wimbledon Women's Finals - 2003-07-05

Serena has five major titles, and is 39-1 in her past six grand-slam events. She holds a 6-5 edge in head-to-head matches with her older sister, and won the last five times they met.

The men's final on Sunday will crown a first-time grand-slam winner as 26-year-old unseeded Australian Mark Philippoussis takes on 21-year-old Swiss star Roger Federer - the fourth seed.

Both won semifinal matches Friday by identical 7-6, 6-3, 6-3 straight-set scores.

Philippoussis downed unseeded Frenchman Sebastien Grosjean, while Federer defeated fifth-seeded American Andy Roddick to become the first Swiss man ever to reach a grand-slam final.

Two years ago, Federer ended Pete Sampras's 31-match Wimbledon winning streak.

Philippoussis is trying to become the third unseeded men's champion at Wimbledon since seeding began in 1927. He is coming back from a severe left knee injury at last year's U.S. Open that left him in a wheelchair for three months.