Tale of two sisters in Aussie quarters

MELBOURNE, Australia -- One Williams sister came back from the brink in the Australian Open quarterfinals on Wednesday. The other blew a big lead.

Do we really need to tell you which one did what?

Yes, it was 11-time Grand Slam champion Serena Williams who rallied against temperamental baseliner Victoria Azarenka, eking out a 4-6, 7-6 (4), 6-2 victory in front of an appreciative crowd at Rod Laver Arena. Azarenka, playing lights-out, led the world No. 1 4-0 in the second. The end result adds to Serena's big-game reputation, and fans knew they were watching a great champion.

Before Serena's match, Venus collapsed against China's Li Na 2-6, 7-6 (4), 7-5 in nearly three hours of error-strewn tennis. Venus, turning 30 in June, failed to serve out the encounter at 5-4 in the second.

"I felt confident going into the match and I felt confident in the match," said Venus, who also lost to Li at the 2008 Olympics in Beijing. "The thing about tennis is you really have to close it out. I didn't do that, unfortunately."

The sixth seed was on the verge of reaching only her second non-grass semifinal at a major since losing to Serena in the 2003 Australian Open final. Grand Slam title No. 8, and a first outside Wimbledon since 2001, will have to wait.

"Serena is one of a kind," said retired Grand Slam champion Mats Wilander, an analyst for Eurosport. "It doesn't look like Venus is hitting the ball with a lot of confidence. She's just trying to win by being physically stronger and faster than other girls."

Comebacks are nothing new for Serena in Oz. En route to her first two titles in Melbourne, Serena saved match points. Claiming the Australian Open in the odd years of 2003, '05, '07 and '09, Serena remains on track to end the sequence -- and won't mind one bit.

It looks like we'll see the dream final between Serena Williams and Justine Henin. Williams is almost a guarantee against Li in the semis, with an 8-1 record in her previous nine Grand Slam semifinals. Henin, a seven-time Grand Slam champ, faces Zheng Jie in Thursday's other semi. Finally, the Belgian gets someone her own size.

If Serena hadn't turned it on, it would have marked the second time in less than two years that the siblings exited a Slam on the same day. In the third round of the '08 French Open, Serena fell to Katarina Srebotnik and, about eight hours later, Venus tumbled to Flavia Pennetta. Clay has never been overly friendly to Americans.

Azarenka, seeded seventh, is one of those players destined to land a Grand Slam in the future. In the first six months of '09, Azarenka sizzled, topping Serena -- albeit a hobbled one -- in her own backyard at the Sony Ericsson Open. The native of Belarus also led Serena by a set in the fourth round of last year's Australian Open before succumbing to a heat-induced illness.

Williams, still playing with strapping to her left leg, didn't panic when she was down and seemingly out. She stayed calm, even as Azarenka took a 3-1 lead in the tiebreaker. The third set was a mere formality.

In this case, stats don't lie: Minus-6 in the unforced errors-to-winners differential in the first set, Serena was plus-10 in the second and she downright sizzled in the third, thumping 18 winners and a paltry three unforced errors. Her first-serve percentage soared to 65 in the third.

Venus' serve was pivotal, too. Not the way she would have hoped.

"Her biggest weapon is her serve, but her biggest weakness is her serve," Venus' hitting partner, David Witt, said. "That says it right there. When she's serving unbelievable, she's wiping people off the court."

No one forecast the serve would be a topic of discussion when Venus stepped up for a spot in the semis. When the match was only around an hour old, in the 10th game of the second, Venus made 2 of 5 first serves. In the third set, when the breaks flowed, Venus' percentage dipped to 40. Twice she failed to hold break advantages.

The sun was a factor, and Venus threw in 11 double faults. Adding to the ugliness, the duo combined for 110 unforced errors. Venus actually won more overall points.

"She got into a position to win it at 5-3 in the second," Witt said. "And if your first serve isn't going in, you have to tell yourself to stop going for the big serve, you have to spin it in and you have to kick serve. I think if she would have, she would have won the match. It's hard when you're out there, but that's what you have to do. I think this one is going to sting a little for her."

China has never had two players in a Grand Slam quarterfinal, but now has two in the semis. Li, ravaged by injuries, won't change her patterns heading into the semis, continuing to visit Chinatown for Chinese food.

The 27-year-old might even treat herself to a beer for cracking the top 10.

"I think the important thing is to enjoy the day, and then try to refocus on the evening," Li's Swedish coach, Thomas Hogstedt, said. "I think that's the toughest challenge for her, to get motivated. I'm sure she will, but it's important to put this in the back of her mind and think about tomorrow."

With the loss, Venus has plenty of time to think.

Ravi Ubha is a frequent contributor to ESPN.com.