MELBOURNE, Jan. 17 (Xinhua) -- China's Zheng Jie failed to make into the fourth round at the Australian Open after she losing to Aussie wildcard Casey Dellacqua in straight sets her on Friday.

Dellacqua raced through the first set in 33 minutes and broke Zheng's serve again in the opening game of the second set. Zheng, a former Australian Open and Wimbeldon Open semifinalist, got back on level terms.

But the Chinese took a five-minute medical timeout to be treated for heat stress after the seventh game.

Though she dropped her serve immediately after the resumption, 28-year-old Dellacqua broke straight back and then served the match out.

"I think she adapted better to the hot weather," said Zheng. "And I played my worst match of the tournament today."

Zheng miscued several shots, recording 28 unforced errors and had her serve broken five times during the match.

Dellacqua will now meet Canadian teenager Eugenie Bouchard on Sunday for a place in the quarterfinals.