Melbourne - Serena and Venus Williams won their eighth Grand Slam women's doubles title on Friday with a 6-3, 6-3 win over Daniela Hantuchova of Slovakia and Japan's Ai Sugiyama.
The Williams sisters, seeded 10th, looked unflustered in the Australian Open final as they served out the first set in just 38 minutes under a closed roof on centre court.
The second set proved more difficult as the pairs exchanged breaks six times in nine games before the Williams' powerful returns and superior movement around the court proved the deciding factor.
Serena Williams, who returns to centre court on Saturday for the singles final, dominated at the net as they broke Sugiyama's serve to take a 4-3 lead, then sealed the championship by breaking Hantuchova.
The sisters, who won the women's doubles gold medal at last year's Beijing Olympics, held up their rackets to celebrate the win before hugging each other on court.
"I'd like to thank Serena for being the best partner," Venus Williams, 28, said. "I wouldn't want to play with anyone else. She's amazing."
The Williams sisters now have three Australian Open doubles titles, having previously won here in 2001 and 2003.
Serena, 27, who has a chance to win her 10th singles Grand Slam title when she takes on Dinara Safina on Saturday, looked relaxed during and after the match.
The sisters laughed and chatted between sets and made an unhurried exit from Rod Laver Arena after the trophy presentations.