She came from a set down in the US Open last night.
Serena Williams remains on course for a record equaling 24th Grand Slam singles title.
The six time US Open champion came from a set down to reach the last four of the tournament by beating Tsvetana Pironkova of Bulgaria.
She'll now face unseeded Victoria Azarenka, after the Belarusian thrashed Elise Mertens 6-1, 6-love.
In the men's draw, Dominic Thiem beat Alex de Minaur in straight sets.