Berlin,  American tennis player Coco Gauff reached the quarterfinals of German Open after registering a 6-0, 6-4 win over Chinese qualifier Wang Xinyu in just 63 minutes, here on Thursday.

The 18-year-old Gauff won the first seven games of the match, but needed to come from a break down in the second set. Wang broke her serve for the first time at 1-1, but Gauff won five of the last six games of the match.

On the other hand, Veronika Kudermetova sealed the final quarterfinal berth with a 6-3. 6-7(5), 6-1 win over defending champion Liudmila Samsonova. After coming from 6-2, 5-2 down to defeat Aryna Sabalenka in Round 1, Kudermetova responded admirably to the reverse when it was Samsonova who rallied from a big deficit.

Kudermetova led the match, 6-3, 4-0, and failed to convert on a match point in the 10th game of the second set. Samsonova, who won the title as a qualifier 12 months ago, sent the match the distance on her fifth set point, barely hanging on after opening up a 6-1 lead in the tiebreak.

However, Kudermetova started strongly to dominate the decider; she crucially saved five break points serving at 2-0, and sealed the win in 2 hours, 9 minutes.

"I started to play really slow. I gave her a lot of chances and I started to make a lot of mistakes," Kudermetova said.

"This surface, you need to play aggressively. If you start to slow down, you'll lose. ... (in the third set), I started to play more inside the court; if I had chances, I started to play more aggressive," she added.

Kudermetova, in form on grass this summer after reaching the semifinals of the Libema Open last week, will next face No 8 seed Belinda Bencic.