Karolina Muchova booked her spot in the semi-finals of the Stuttgart Open after defeating Coco Gauff for the first time in her career.

Muchova triumphed 6-3 5-7 6-3 in two hours and 22 minutes against the second seed to continue her impressive 2026 campaign.

It was a straightforward enough first set for Muchova, who converted two of her three break points, and conceded none, on her way to taking the lead.

After four consecutive holds to start the second, there were then four straight breaks of serve as both players struggled to control the set.

Gauff eventually took the second set with a third break coming in the 11th game, but the American could not carry that momentum into the decider.

After saving two break points in the opening game of the third, Muchova took Gauff's serve in the sixth game and did not look back, clinching victory with her first match point.

Muchova will face Elina Svitolina in the semi-finals after the fourth seed defeated Linda Noskova 7-6 (7-2) 7-5 earlier on Friday.

Data Debrief: Muchova thriving in 2026

After six career losses against Gauff, two of which came this year, Muchova finally got the better of her American counterpart.

Muchova is now through to her fourth semi-final of 2026, previously reaching the last four at the Miami Open (lost to Gauff), Brisbane Open (lost to Aryna Sabalenka), and Doha Open (won the tournament).

Gauff, meanwhile, continued to struggle on serve. Across her two matches in Germany, she won just 17 of her 25 service games.