Serena Williams continued her bid to retain the US Open title by beating Italy’s Flavia Pennetta 6-4 6-3 in their quarter-final overnight.
The defending champion moved into the semi-finals to set up a clash with comeback queen Kim Clijsters by comprehensively outclassing 10th seed Pennetta.
Williams, who is bidding to win the Flushing Meadows crown for the fourth time, faces Clijsters after she beat 18th seed Li Na earlier.
Williams' serve played a significant part in her victory as she hit seven aces and finishing with an 86% first serve success.
The American is now relishing a showdown with the returning Clijsters, who made her comeback after more than two years in retirement.
“She is such a great person and I only wish the best for her – though not in the next match of course,” Williams said after disposing of Pennetta.
“It’ll be a great match. She has nothing to lose and is having so much fun, which makes me so happy.
“Initially I was surprised how well she’s been doing but she did so well a couple of weeks ago that I knew she was someone to look out for.”