Agnieszka Radwanska ends Naomi Broady's hopes of making progress at the US Open

The Polish world No 4 came through an epic first set tiebreak against the 26-year-old from Stockport and got the job done with a single break off serve in the next set to extend her winning run to six matches.

Radwanska,who has never won a Grand Slam title, came into Flushing Meadows on the back of winning the Connecticut Open title last weekend and was forced to show all her defensive attributes to save four set points before eventually coming out on top 11-9 in a thrilling tie-break.

That proved to be the crucial moment in the match as the Pole went on to claim the second set in more convincing fashion and seal victory.

"She was serving unbelievable," Radwanska said. "120mph serves are not easy to return."

"I'm so pleased I could come back in that first set," said added. "It was the key set. There was a lot of running and a lot of struggling but it was another two sets for me."

Radwanska will play French hope Caroline Garcia next for a place in the fourth round.