The American superstar won her last Grand Slam at the 2017 Australian Open when she was two months pregnant with her daughter Alexis Olympia Jr. And yesterday Williams, who turns 39 later this month, faced Bulgarian mum Tsvetana Pironkova who was playing her first event since Wimbledon 2017 after giving birth to her son Alexander in April 2018.
Unranked Pironkova took the first set and led by a break in the second before Williams quelled her anxiety to battle back to win 4-6 6-3 6-2 to reach her 14th US Open semi-final in her 20th appearance.
Williams is bidding to equal the record of 24 Grand Slam singles titles held by Margaret Court. And become the fourth woman in the Open era to win a major title as a mother after Court, Evonne Goolagong and Kim Clijsters.
She will now face the winner of the second quarter-final between Victoria Azarenka and Elise Mertens.