MELBOURNE, AUSTRALIA - Serena and Venus Williams won their eighth Grand Slam women's doubles title Friday with a 6-3, 6-3 victory over Daniela Hantuchova and Ai Sugiyama.

The Williams sisters, seeded 10th, looked unflustered as they served out the first set in 38 minutes under a closed roof.

After both paris exchanged breaks in the second set, the Williamses' powerful returns and superior movement proved to be the deciding factor.

The men's doubles title could belong to siblings, too. Twins Bob and Mike Bryan will face Mahesh Bhupathi and Mark Knowles on Saturday.

Closing the roof

There was no confusion about the Extreme Heat Policy on Thursday, the second day of what forecasters were predicting could be a once-in-a-century heat wave.

Rod Laver Arena's retractable roof was closed long before the first match and all outdoor matches were postponed.

Serena Williams and Svetlana Kuznetsova played through 107-degree heat in the first set of their quarterfinal.

Then the tournament's Extreme Heat Policy came into effect and the roof was closed. Lucky, too. The temperature rose above 109 degrees.