Former world No. 1 Wozniacki upset in 1st-round loss to Pervak at Brisbane International

Caroline Wozniacki, of Denmark, plays a return shot during her first round match against Ksenia Pervak, of Kazakhstan, during the Brisbane International tennis tournament in Brisbane, Australia, Monday, Dec. 31, 2012. (AP Photo/Tertius Pickard) (The Associated Press)

Ksenia Pervak, of Kazakhstan, reacts after winning a point during her first round match against Caroline Wozniacki, of Denmark during the Brisbane International tennis tournament in Brisbane, Australia, Monday, Dec. 31, 2012. (AP Photo/Tertius Pickard) (The Associated Press)

Caroline Wozniacki's first trip to the Brisbane International ended in a shocking 2-6, 6-3, 7-6 (1) first-round loss to Kazakhstan qualifier Ksenia Pervak on Monday.

Wozniacki, who held the year-end No. 1 ranking in 2010 and 2011 but is yet to win a major title, had high-profile support from boyfriend and top-ranked golfer Rory McIlroy in the crowd. But she struggled with her serve as she lost the second set and then had difficulty in the third countering powerful groundstrokes from the left-handed Pervak.

The 103rd-ranked Pervak was two points from victory, serving for the match at 5-3 and 30-15, but made a series of unforced errors to let the 10th-ranked Wozniacki back into it. Pervak dominated the tiebreaker, though, winning the first five points.