Coco Gauff has progressed to the next round at the Linz Open in Austria. Photo: Adam Hunger/AP Photo

American teenager Coco Gauff stunned top seed Kiki Bertens to advance to her maiden WTA semi-final with a 7-6(1) 6-4 victory at the Linz Open in Austria on Friday, then went back to her hotel to do her schoolwork.

Gauff, 15, became the youngest player to reach a WTA semi-final since Czech Republic's Nicole Vaidisova won the Tashkent Open in 2004, also aged 15.

After taking the opening set in a tiebreak, Gauff needed only one break of serve to wrap up the match in 97 minutes for her first career win over a top-10 player.

Gauff had no time to think about her achievement, though, concentrating instead on the schoolwork that awaited her back in her hotel room.

"I just got off the court, so I've not thought about the semi-final," said Gauff, who plays Germany's Andrea Petkovic in the last four.

"I'm thinking of the homework I have to do tonight. I don't know what it is yet. I'm studying the typical stuff – Math, English, History... I don't know what I have to do but I know it's something."

Gauff shot to fame this year when she became the youngest player to qualify for the Wimbledon main draw in the Open era and reached the fourth round, beating veteran Venus Williams along the way.

The American was fortunate to advance to the second round of the Linz Open after getting a lucky loser draw less than an hour before Tuesday's match was set to begin.

Gauff will become the only player under the age of 18 in the top 100 when the rankings are updated on Monday. She is also in the doubles semi-finals in Linz, partnered with 17-year-old compatriot Caty McNally. 

Reuters