Caroline Wozniacki says it 'really sucks' after US Open second-round exit

"Here, not playing my best level, but still being so close, and still having my chances but not closing it out, that hurts."

Fourth seed Caroline Wozniacki spurned four match points as she crashed out of the US Open second round in a final-set tie-break against Petra Cetkovska.

Wozniacki, who was runner-up at Flushing Meadows in 2009 and 2014, appeared to have the match in her grasp after she came from a set and 4-1 down to lead 6-5 in the decider.