Coco Gauff's first match since winning the French Open did not go to plan as she was knocked out of the Berlin Open by Wang Xinyu on Thursday.
The American struggled to find her best, with Wang taking full advantage in a 6-3 6-3 victory in 75Â minutes to reach the last eight.
Gauff had to defend two break points in the opening game, but held serve, matching Wang blow for blow in the opening stages.
However, Wang broke to love to take a 4-3 lead and took the first set at the second time of asking to finish off a four-game winning streak.
Gauff then attempted to launch a fightback, earning her first break on the way to taking a 3-1 lead, but she could not hold onto her momentum.
Wang strung together a five-game streak this time, breaking Gauff twice more before converting her second match point to set up a meeting with Paula Badosa in the quarter-finals.
Data Debrief: Wang shows grass-court dominance
Gauff was playing as a two-time grand slam champion for the first time, but Wang ensured her switch to grass did not go smoothly.
Wang earned her third top-10 win in quick fashion, with this the biggest victory of her career, and forced 11 break points against Gauff, converting four of those.
She was helped in part by Gauff, who made seven double faults to Wang's one, while the world number two's first serve percentage sat at 38%.
