American CoCo Vandeweghe has shocked world No.1 Simona Halep in straight sets to move into the semi-finals of the Porsche Tennis Grand Prix in Stuttgart.
The Pat Cashed-trained Vandeweghe, who won 6-4 6-1 in an hour and 14 minutes, fired five aces and 19 winners to exert her dominance in the clay court event despite previously stating her dislike for the surface.
The US Open semi-finalist raced to a 5-4 lead in the opening set on the back of her strong service game.
The 26-year-old then sealed a decisive break to clinch the first set and gain the upper hand in the contest.
Despite stepping up her attack, Romania’s Halep struggled to find a way past her opponent who cruised through the second set to reach the last four of a claycourt event for the first time.
Vandeweghe next takes on sixth seed Caroline Garcia who later overcame Ukraine’s Elina Svitolina 6-7 (7-4) 6-4 6-2 in two hours and 16 minutes.
Estonia’s Anett Kontaveit also advanced with a hard-fought 7-5 6-7 (6-8) 6-4 victory over Russian Anastasia Pavlyuchenkova.
Kontaveit prevailed after 2 hours 55 minutes on her fourth match point when Pavlyuchenkova hit a groundstroke wide.
The final set of the hard-hitting encounter of unseeded players saw breaks of serve in the last seven games.
“The whole match was so close,” Kontaveit said. “I am trying to go for it whatever the score is. I just kept fighting.”
On Saturday, she meets either French Open champion Jelena Ostapenko of Latvia or Czech fifth seed Karolina Pliskova.