NEW YORK - Denmark's Caroline Wozniacki beat the heat and Maria Sharapova 6-4 2-6 6-2 to move into the quarter-finals of the US Open on Sunday as another top seed disappeared under a broiling Flushing Meadows sun.

The brutal conditions turned the match between the fifth seeded Sharapova and the 10th seeded Wozniacki into a battle of survival.

After Wozniacki took the opening set and Sharapova leveled the match officials declared the heat rule in effect, both players leaving the sizzling stadium as soaring temperatures and stifling humidity made conditions too dangerous to play.

Action resumed 12 minutes later but not before Sharapova was warned for not returning to the court on time.

Wozniacki, a former world number one looking for her first grand slam title, claimed an early break in the third to go up 3-1, then finished off the five-time grand slam winner with backhand winner down the line.