The only remaining Aussie singles seed delivered a string of lethal winners in an entertaining 6-3, 3-6, 6-4 win.
Delacqua’s win was made all the more impressive by her capitulation to the same opponent in their only other meeting in Malaysia last October.
The Perth leftie was outside the world’s top 200 rankings after the Flushing Meadows tournament last year but has rocketed up the rankings into the top 25.
“It’s awesome for me because I’ve never been past the second round here at the US Open before and I’ve worked really hard the whole year,” Dellacqua said.
She next faces Flavia Pennetta on Monday for a place in her first grand slam quarter final.
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