Second seed Victoria Azarenka beat Slovakia's Daniela Hantuchova 6-2 6-3 on Wednesday to set up a U.S. Open semi-final clash with Italy's Flavia Pennetta.
Belarusian Azarenka, the beaten finalist at Flushing Meadows last year, took control after breaking Hantuchova with a superb backhand to go 5-2 up in the first set.
Hantuchova, ranked 48th in the world, made a determined start to the second set though, holding her serve and then going 2-0 up, breaking thanks to well-placed volley.
But Azarenka hit back immediately with a break and that clearly rattled her Slovak opponent, who proceeded to make a series of unforced errors.
Azarenka had three break points in the fifth game but lost them all, only for Hantuchova to double-fault twice at deuce and gift her the game and a 3-2 lead.
The Belarusian had service struggles of her own and gave Hantuchova a glimmer of hope with a double-fault that gave up a break to make it 5-3, but again the Slovak was unable to capitalize and Azarenka ran out the comfortable winner.