The defending champion and world No 1, Iga Swiatek, showcased all her experience to book a semi-final place at the Porsche Tennis Grand Prix in Stuttgart.
Swiatek fought back from a set down against Karolina Pliskova to claim a 4-6, 6-1, 6-2 victory. She will now face the Tunisian Ons Jabeur, who dropped only three games in seeing off Beatriz Haddad Maia 6-3, 6-0.
Swiatek is one win away from reaching the final in her first tournament for over a month after suffering a rib injury.
The world No 2, Aryna Sabalenka, will meet Anastasia Potapova in the second semi-final after Sabalenka beat the wild card Paula Badosa 4-6 6-3 6-3.
In the men’s Barcelona Open, Britain’s Dan Evans booked a semi-final place with a comeback victory over Argentina’s Francisco Cerundolo. Evans lost the first set, but responded in high-class fashion to secure a 2-6, 7-5, 6-3 triumph.
Evans will face the defending champion and top seed, Carlos Alcaraz, at the last-four stage on Saturday after Alcaraz saw off his fellow Spaniard Alejandro Davidovich Fokina in straight sets.
And the other semi-final sees Stefanos Tsitsipas meeting Lorenzo Musetti, who had a walkover in his quarter-final.
Meanwhile, in Bosnia Novak Djokovic suffered a shock defeat in the Srpska Open quarter-finals with a straight sets loss against Dusan Lajovic.
It was the first time that world No 1 Djokovic had lost to a fellow Serbian since Janko Tipsarevic beat him 11 years ago.
Djokovic, who admitted during his pre-tournament press conference that he had been battling an elbow issue, lost 6-4, 7-6 at Banja Luka on the Bosnian clay.
For Lajovic, it was only his third career victory against a player in the top five of the world rankings.
It was Djokovic’s third defeat of the season, with the Madrid Open his next scheduled tournament, starting later this month.
“I am overwhelmed, it is the biggest win of my career,” Lajovic said in his on-court interview, reported by www.atptour.com.
“The emotions are very mixed because I’m playing here in front of the home town and I’m also playing against a good friend and he’s a hero of our country.
“Beating him, it’s something that I didn’t even think was going to be possible, but it happened.
“His percentage of the first serve was not the greatest, so I was able to use that to my advantage. But overall, I think it was very good tennis from my side.”