MELBOURNE, Australia -- Kim Clijsters' duel with Li Na promised much. They played a high-level match in Sydney last year, then did the same in the Australian Open final a few weeks later. Clijsters won the more important of the two contests to finally end her non-U.S. Grand Slam drought.
Sunday's encounter wasn't as clean, but who cares? It was far more dramatic and kept the defending champion in the tournament. Clijsters saved four match points in a second-set tiebreaker and progressed to the quarterfinals with a 4-6, 7-6 (6), 6-4 win.
And here we thought there was a sense of inevitable -- a Li victory -- after Clijsters rolled her left ankle in the seventh game. Apart from squandering those match points, Li blew a break advantage in the second set.
What happened: Li, simply, tightened in the tiebreaker. Leading 6-2, she missed consecutive crosscourt forehands. Worse was to come at 6-5, the stuff of nightmares. Clijsters bailed on the point by hitting a drop shot, an ineffective one. Li was there in ample time but pushed her backhand almost straight at Clijsters, who then hit a safe, winning lob.
Speaking of the inevitable, Clijsters cruised past a devastated Li in the third set -- she took a 5-1 lead -- to advance to the quarterfinals.
Don't forget about: With all the tension late in the tiebreaker, it's easy to forget about the third point. But it was pivotal. Li thought she won it with an ace, which would have given her a 3-0 lead. Clijsters correctly challenged, and Li double-faulted to make it 2-1.
All credit to Kimmy: Clijsters hasn't always acquitted herself admirably with injuries. Think back to last season in Indian Wells against Marion Bartoli, when Clijsters retired with a shoulder injury; it looked to be a half-hearted effort before Clijsters called it a day. Clijsters, however, was intent on seeing this one through in the wake of retiring in Brisbane with a thigh problem. She willed herself on with multiple fist pumps. The adrenaline pumping, she hit all four of her aces in the third set.
What of the ankle?: Clijsters will be ultra-confident after the win and on a high. But her ankle is a concern. How will it feel Monday and Tuesday? Her next opponent is either Caroline Wozniacki or Jelena Jankovic, two players who'll make the Belgian strike a lot of balls -- more than Li.
Tough one to swallow for Li: Li had difficulty winning a match from Wimbledon onward in 2011. She admitted the pressure of being a Grand Slam champion affected her. Refreshed following a solid training block in Germany in the offseason, she began 2012 in impressive fashion, venturing to the Sydney final. This loss will set her back. Questions will be asked, again, about her mental toughness.
London-based Ravi Ubha covers soccer and tennis for ESPN.com. You can follow him on Twitter.