Caroline Wozniacki: 'US Open second-round exit really hurts'

Former world number one Caroline Wozniacki has admitted that it "really hurts" to have been knocked out of the US Open in the second round.

The fourth seed suffered a shock three-set defeat to Petra Cetkovska on Thursday.

Wozniacki, who made the final at Flushing Meadows last year, is the seventh top-10 seed to be knocked out in these early stages.

"It really sucks to lose a match like that," Wozniacki told reporters. "Here, not playing my best level but still being so close, and still having my chances but not closing it out, that hurts. That really hurts."

Wozniacki is yet to win a Grand Slam in her career.