VikaRR

Relishing their shared return to tournament tennis, Victoria Azarenka and Andrea Petkovic stood toe-to-toe in producing pulsating exchanges. Then came the fall. A streaking Petkovic rolled her right ankle chasing a running forehand on the red clay, crashed to the court, and hobbled off, arm-in-arm with Azarenka.

The world No. 1 advanced to the Stuttgart quarterfinals after a painful conclusion to a match that offered its share of quality rallies. Azarenka led 6-2, 4-4, when the edge of Petkovic's right shoe stuck in the dirt, sending her tumbling to the court behind the baseline. Lying on her back, Petkovic immediately removed her shoe. A concerned Azarenka came over, clutching an ice bag, and Petkovic reached out to shake hands in a sign she could not continue.

"It's such a tough situation; the ankle right away blew up and there's nothing you can really do," Azarenka told Heinz Gunthardt in her on-court interview. "I feel really sad. She just came back from injury. It was really a terrible way to finish the match."

In her first match since her 26-match winning streak came to an end with last month's Miami quarterfinal loss to Marion Bartoli, an eager Azarenka showed few signs of rust in breaking to open the match. Serving at 2-1, Azarenka's trademark shriek turned to a fretful squeal as she sailed a backhand swing volley wide to drop serve for 2-2. That was one of her few miscues of the first set. The top seed danced around a second serve and drilled a diagonal return winner to break for 3-2, sparking a spurt that saw her win four consecutive games to close the first set.

Spare a thought for Petkovic, who last year became the first German woman since Steffi Graf in 1998 to finish a season ranked in the Top 10, but suffered a lower back injury that sidelined her for three-and-a-half months this season. Playing with tape on her knee, a spirited Petkovic competes with the genuine joy of one who loves her job, but her body has betrayed her in recent months. She shook off a bloody nose during the changeover after the seventh game and twice fought back from a break down in the second set. Trailing 2-4, Petkovic fought off a pair of break points and held with a ferocious forehand swing volley and fist pump for 3-4. She broke at 30 to level the set before suffering the match-ending injury.

Azarenka's coach, Sam Sumyk, scribbled notes with the speed of a stenographer, and must be satisfied with what he saw from his charge. Her footwork and ball striking were both sharp. She lost a bit of depth on her second serve in the second set, but returned effectively, converting five of 11 break-point chances. Azarenka will face German wild card Mona Barthel in the quarters. Vika rallied for a 6-4, 6-7, 7-6 win over Barthel in their last meeting in Indian Wells, a month after sweeping the German, 6-1, 6-0.