Serena Williams dominates Venus withdraws

Williams sisters: Serena dominates, Venus withdraws

While Serena continued her summer comeback, defeating her first three opponents in straight sets on way to the round of 16, big sister Venus withdrew on Day 3 Wednesday due to Sjögren's Syndrome, an autoimmune disease that she said has been causing fatigue and joint pain.

Despite her No. 28 seed, Serena came in as the consensus favorite and proved to be just that, dropping only three games in her first two matches against Serbia’s Bojana Jovanovski and the Netherlands’ Michaella Krajicek, respectively. In the third round, the 29-year-old three-time Open champion looked poised to take a fourth, knocking out the No. 4 seed Victoria Azarenka of Belarus, 6-1, 7-6(5).

Next up, Serena will face No. 16 seed Ana Ivanovic of Serbia, the 2008 French Open champ, who has also breezed through her matches in straight sets. The road from there should only get tougher as five top-10 seeds remain: No. 1 Caroline Wozniacki, No. 2 Vera Zvonareva, No. 7 Francesca Schiavone, No. 9 Samantha Stosur and No. 10 Andrea Petkovic.

As for Venus, after calling it quits before her second-round match against Germany’s Sabine Lisicki she said she hopes to return to the court "soon." A two-time Open champ, the 31-year-old beat Vesna Dolonts of Russia in the first round.

Serena & Entire Top 20 In Toronto Field

Serena & Entire Top 20 In Toronto Field

TORONTO, Canada - The entire Top 24 plus a legendary player trying to work her way back up the rankings will descend on Toronto this week for the prestigious $2,050,000 Rogers Cup, held at the Rexall Centre in Toronto.

Watch Toronto all week on WTA Live powered by TennisTV!

World No.1 Caroline Wozniacki leads the field as the top seed, and will look to get back on track after early losses at Roland Garros and Wimbledon - as well as at her only tournament since the grass court season in Bastad, where she had to retire from her second round match due to a right shoulder strain. One year ago Wozniacki went all the way to the title here and after a bye begins her defense against either Yanina Wickmayer or Roberta Vinci.

World No.2 Kim Clijsters has only played two tournaments in the last four months due to a series of injuries (shoulder, wrist, ankle) but is back on the courts and ready to make her first appearance of the summer in Toronto. Like Wozniacki, Clijsters has also raised the trophy here before, winning it in 2005. Also the recipient of a first round bye, she kicks off with a qualifier.

Vera Zvonareva, Victoria Azarenka, Maria Sharapova, Li Na, Petra Kvitova and Francesca Schiavone are seeded No.3 through No.8. French Open champion Li and Wimbledon champion Kvitova will be playing their first tournaments of the summer hardcourt season, as will Schiavone.

Schiavone is doing an ESPN live chat Monday at 3pm ET - click here!

Marion Bartoli, Sam Stosur, Andrea Petkovic, Svetlana Kuznetsova,Agnieszka Radwanska, Anastasia Pavlyuchenkova, Jelena Jankovic andDominika Cibulkova are seeded No.9 to No.16, respectively.

Another star in the draw will be Serena Williams, who returned from a year-long injury and illness lay-off before Wimbledon. Although she is ranked down in the 70s, she has even fewer tournaments on her points total with three, and just over a week ago made an emphatic run in Stanford, winning the first WTA title of her comeback (beating Sharapova, Sabine Lisicki and Bartoli in the last three rounds). She begins against former Top 20 player Alona Bondarenko.

Serena Williams winner's trophy Bank of the West Classic tennis tournament in Stanford, Calif

Serena Williams, of the United States, poses with the winner's trophy after beating Marion Bartoli, of France, 7-5, 6-1 in the final of the Bank of the West Classic tennis tournament, in Stanford, Calif