Elbow room was limited in the Dubai photo pit for today's showdown between two photogenic, former No. 1s. While Ana Ivanovic showed flashes of the form she displayed in winning the 2008 French Open—along with nine double faults, caused mostly by chasing stray service tosses—Caroline Wozniacki was a picture of consistent focus.

The defending champion withstood a barrage of blistering forehands to reach the semifinals with a 6-3, 7-5 victory that offered some startling winners and a share of mind-numbing misses from Ivanovic, who committed more than twice as many unforced errors (51 to 22) as the quick-footed counterpuncher on the other side of net.

This was territorial tennis, with both women trying to impose their preferred pattern of play. Wozniacki, whose two-handed backhand is her best shot, targeted Ivanovic's two-hander, while the Serb, who can dictate play and dominate points with her flat forehand, tried to break down Wozniacki's weaker forehand wing, a tactic her coach, Nigel Sears, summed up with his "drill the forehand" declarative during a coaching consultation five games into the match.

The third-seeded Dane, who netted successive forehands to blow a break point in the second game, managed that side more effectively in breaking for a 4-2 lead, then fought off four break points in the seventh game to dig out of an 0-40 deficit and hold for 5-2. Two games later, a tame Ivanovic drop shot sat up as if placed on a tee, and Wozniacki sprinted forward to blast a backhand winner, seizing the opening set in 39 minutes.

There's a vulnerability beneath the visor Ivanovic wears that can creep to the surface and sabotage her serve. She slammed an ace down the middle for an emphatic hold to start the second set, only to dump two double faults and donate a break two games later. Ivanovic can lose the plot quickly when things go wrong—her toss goes awry, and the uncertainty unsettled her, only to bounce back with a streak of winners.

Wozniacki held for 3-1 before Ivanovic, whos angst was apparent in a rigid right arm, started to shake off the constraints and swing more smoothly to break back for 3-3. That started a run of six straight service breaks, as Ivanovic beat Wozniacki to the punch with her forehand, but Caro would not beat herself. She continued to track down balls and strike with her backhand, whipping a backhand winner down the line to break for 6-5. Wozniacki won 23 of 31 points played on Ivanovic's second serve.

Serving for the match, Wozniacki opened with an ace. On her second match point, the pair produced a high-quality, 24-shot, running rally that concluded with Ivanovic poking a backhand long.

"I just tried to hold pressure on the backhand and tried to move her on the forehand," said Wozniacki, who will face Julia Goerges or Daniela Hantuchova for a spot in the final. "She may have one of the strongest forehands in the women's game so you don't want to keep her over there too long."

—Richard Pagliaro