MELBOURNE, Australia -- Thursday was not a great day for the Williams sisters at the Australian Open.
Venus Williams was knocked out of the women's singles draw, losing 2-6, 6-3, 7-5 to 46th-ranked Carla Suarez Navarro of Spain, while Serena Williams ignored pain and frustration to reach the third round of the Australian Open with a straight-sets win over Gisela Dulko.
Venus Williams hardly looked like the reigning Wimbledon champion against the 20-year-old Suarez Navarro, whose previous best showing in a Grand Slam was reaching the French Open quarterfinals last year.
Usually the aggressor with her powerful shots, the sixth-seeded Williams was sluggish as she squandered a match point and dropped the last five games with the crowd cheering loudly for Suarez to finish off the victory.
"She was super-consistent and aggressive and just went for her shots," said Williams, who has seven Grand Slam titles and now will have to hope for a doubles crown here with sister Serena. "Probably one of her best matches she's ever played.
"I wasn't in control of the points. I'm definitely used to dictating the points a little bit more. It was kind of a pattern that wasn't the best for me."
Suarez Navarro, overmatched at first, broke twice in the second set as Williams let a number of reachable shots fly past. She saved a match point while serving at 4-5 in the deciding set and broke Williams in the next game, aided by a double fault from the American.
Suarez Navarro squandered one match point while serving at 40-15 in the next game before Williams netted a forehand for her 37th enforced error, and Suarez Navarro said she had little choice but to turn up the pressure.
"You must be aggressive during all the match," she said. "If not, she's going to take control of you."
Serena Williams, meanwhile, headed straight to the practice courts for extra work after her 6-3, 7-5 win over Dulko. She gave her performance a "D-minus at best" as 45th-ranked Dulko matched her shot for shot.
"Lots and lots and lots of room for improvement," second-seeded Serena Williams said. "But it's good that I was able to win, too, when I wasn't playing my best."
Serena Williams, hoping to extend a sequence of winning the Australian title every alternate year since 2003, had to fend off six set points in the ninth game of the second set to prevent the match going to a third. That game went to a dozen deuces before Serena broke to get back on serve.
She got treatment on her left ankle in the changeover and, grimacing with pain, held and then broke Dulko again -- this game going to deuce a half-dozen times -- to get her chance to serve it out.
After all that, the nine-time Grand Slam winner finished with an ace on her first match point, advancing in 1 hour, 50 minutes.
"It was a very tough second set, she started playing unbelievable, hitting winners left and right," Williams said. "She had a couple of opportunities but I always felt I wasn't going to lose.
"I feel I could play a lot better," she added.
Serena converted only four of her 18 break chances against the 23-year-old Argentine. Dulko was successful on both of hers.
Dementieva, who won titles at Auckland and Sydney before the season's first major, struggled with her serve early but recovered to finish the match in 72 minutes.
The 27-year-old Dementieva reached the French Open and U.S. Open finals in 2004, beaten both times by fellow Russians, and has not returned to the championship of a Grand Slam tournament since.
Her highlight last year was a win over fellow Russian Dinara Safina in the gold-medal match at the Beijing Olympics. She was ousted in the semifinals at Wimbledon and the U.S. Open in 2008 and has never advanced beyond the fourth round at Melbourne Park.
Amelie Mauresmo, who won here and at Wimbledon in 2006, rallied for a 4-6, 6-3, 6-2 win over Britain's Elena Baltacha. Mauresmo, a former No. 1 now seeded 20th after an injury-plagued 2008, advanced when Baltacha double-faulted on match point.
"I'm expecting to play better and better as the tournament will go on," Mauresmo said. "I'm definitely expecting a tougher match, tougher opponent next round. So I will have to step up and play some better tennis."
Other women advancing included No. 8 Svetlana Kuznetsova of Russia; No. 12 Flavia Pennetta of Italy; No. 13 Victoria Azarenka of Belarus; No. 18 Dominika Cibulkova of Slovakia; No. 21 Anabel Medina Garrigues of Spain; and No. 22 Zheng Jie of China.
Information from The Associated Press and Reuters was used in this report.