Germany's Tatjana Maria came from behind to beat compatriot Jule Niemeier 4-6, 6-2, 7-5 on Tuesday and reach her first Grand Slam semi-final.
The 34-year-old mother of two will play either third seed Ons Jabeur or unseeded Marie Bouzkova for a place in the final.
"I have goosebumps everywhere," said Maria, who returned from maternity leave just under a year ago.
"My two little girls, it's a dream to live this with my family, to live this with my two girls. Almost one year ago I gave birth, it's crazy."
She said would like to face world number two Jabeur in the semi-finals.
"It would be really nice to play her," she said. "She is part of my family, she loves my kids, she is playing with them every day."
In only the third all-German Grand Slam quarter-final in the Open Era, Niemeier took control from the start of the match, breaking at her first opportunity and going on to win the set.
The 22-year-old then broke again at the start of the second set to take an iron grip on the match but Maria stormed back, breaking three times to level the match.
World number 97 Niemeier again drew first blood in the deciding set, breaking in the fifth game and holding serve to lead 4-2.
But Maria hit back to level at 4-4 and broke again in the 12th game to seal the victory.
The German veteran, who saved two match points in the previous round, made her Grand Slam debut in 2007 and had never progressed beyond the third round at a major before this year's Wimbledon.