Volkswacht Bodensee - Czech teen upsets Mertens at Miami Open

The Czech wildcard, who arrived in South Florida with a ranking of 279, is making waves at her first major WTA event after upsetting the 24th seed from Belgium 7-5, 2-6, 6-1 in her first contest against a top-50 player.

Fruhvirtova, whose 14-year-old sister Brenda has similarly lofty ambitions, wants to emulate Czech legend Petra Kvitova and capture a Wimbledon title.

Ousting Mertens was a solid first step in that direction. It made Fruhvirtova the youngest woman into the Miami third round since 15-year-old Cici Bellis in 2015.

"It's unbelievable," she told AFP. "I worked really hard for this and I'm enjoying it."

Her powers of recovery for someone so young were particularly impressive. Fruhvirtova was broken at the start and rallied from 0-40 down with the first set poised at 3-3 to take control of the match.

Mertens's experience began to show in a one-sided second set, yet the young Czech was strong enough mentally and physically to steamroll her opponent in the third.

"I want to reach number one. I want to win Grand Slam titles," said Fruhvirtova, who will play former world number one Victoria Azarenka or Ekaterina Alexandrova next.

"We always said that with my sister it's my goal and we just want to achieve that.

"Petra is definitely one of the players that I grew up watching when I was younger. I watched her win Wimbledon two times, so she's definitely someone to look up to."

Following top-ranked Ashleigh Barty's surprise retirement earlier this week, women's tennis has opened up with several young stars pushing for elite spots.

American Coco Gauff, 18, is one of the new wave of potential stars and joined Fruhvirtova in the next round after exacting revenge 7-5, 6-4 on China's Wang Qiang, who beat Gauff at the Australian Open.

Gauff, who faces China's Zhang Shuai next, knows there has been a generational shift with Barty retiring and the likes of Serena Williams edging closer to the end of her storied career.

"Yeah, I would say definitely the game is going through a kind of a shift right now, both sides, women and male side of young players coming up," Gauff said.

"There is a generational shift and I'm glad that I'm a part of it."

Physical and mental demands on players can be daunting to those coming through the ranks.

"What really sets the other players, Grand Slam champions, apart from the rest is probably their mentality," Gauff said. "I'm hoping and have been working on trying to be mentally mature to make it far in Slams and hopefully win one."

O.Krause--BTB