Mother-of-two Tatjana Maria said she would still be changing nappies despite beating German compatriot Jule Niemeier on Tuesday to reach her first Grand Slam semi-final.

The 34-year-old came from behind to win 4-6, 6-2, 7-5 on Court One despite losing the first set and trailing by a break in the second and third sets.

Maria, who gave birth to her second daughter, Cecilia, 15 months ago, will play either third seed Ons Jabeur or unseeded Marie Bouzkova for a place in the final at the All England Club.

But the veteran, who came back from maternity leave just under a year ago, said despite her shock run at Wimbledon, being a mum was the most important thing in her life.

"I'm in the semi-final of Wimbledon, it's crazy, but I'm still a mum," said the world number 103.

"After this I will go out over there and I will see my kids and I will do the same thing what I do every single day.

"I will change her Pampers (nappies), I mean, everything normal. I try to keep normal as much as possible, because what makes me proudest is to be a mum."

Even before her quarter-final on Tuesday it was business as usual for Maria, who took her eight-year-old daughter to tennis practice.

"This morning we arrived at 8:30 indoors and Charlotte, she had a practice," she said. "Yeah, we keep going the same way.

"Outside of the court, I mean, nothing changes for me for a moment, so I try to keep this going, everything the same. We keep going even if I play semi-finals."

In only the third all-German Grand Slam quarter-final in the Open era, an early break for Niemeier proved decisive in the first 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 in two hours and 18 minutes.

The German veteran, who saved two match points in the previous round against 12th seed Jelena Ostapenko, made her Grand Slam debut in 2007 and had never progressed beyond the third round at a major before this year's Wimbledon.

But she said she always had faith in her ability to do something special despite her uninspiring record in the Slams.

"To be now here in this spot -- I mean, like I said, one year ago I gave birth to my second daughter -- if somebody would tell me one year later you are in a semi-final of Wimbledon, that's crazy."