When American teenage sensation Cori Gauff fought back to win from a set and 5-2 down in the semis of the 2017 ITF World Junior Tennis Finals, that was the moment USA girls' captain, Maureen Diaz, knew her protégé was destined for the big time.

Given her meteoric rise, it is hard to believe that only two years ago Gauff was showcasing her skills on the same clay courts of Prostejov as the current crop of talent in the 14 and under age category. To contextualise, last week Gauff was exchanging autographs and posting selfies with former First Lady Michelle Obama.

The 15-year-old has been catapulted into the tennis stratosphere thanks largely to her trailblazing run to the round of 16 at this year’s Wimbledon, during which, as a qualifier, she defeated her idol and five-time SW19 champion Venus Williams.

To complete the half-told story from 2017, Gauff eventually overpowered Maria Timofeeva in that semi-final and then partnered Charlotte Owensby as USA beat Russia 2-1. She was not finished; in the final she dispatched Ukraine's Dasha Lopatetskaya and again teamed up with Owensby to great effect as USA were crowned ITF World Junior Tennis champions.

“That was the moment I thought ‘Coco is going to be a star’,” Diaz told itftennis.com. “There was something about her, something in her, you could see it in her eyes – she had fire. She had presence and still does – it is pretty incredible.

“When she was here in Prostejov, she had this aura about her. Every time she stepped out on court, she was so confident. She knew that she was a very strong player but she did have some tough tests here.

“But in that tie against Russia, she proved what I knew and that was she had the biggest fighting spirit I have ever seen in a player. She had this quality about her, a never-say-die attitude and that is one of the biggest memories I have of her.

“This was such an important tournament in her development. After here it was a rolling ball. It just took off and she kept on improving. From there, you just knew her results would keep on improving and that it was a matter of time before we started to see what we we’re seeing now.”

Diaz is right to highlight Gauff’s post-Prostejov ascent. A matter of weeks later, she reached the girls’ singles final at the US Open before going one better at Roland Garros in 2018, where she was crowned a Junior Grand Slam champion.

Following her exploits at Wimbledon in July, Gauff rocketed into the world’s top 150 and earlier this month won the doubles – her maiden Tour-level title – alongside Caty McNally at Washington. A rapid rise but merely the tip of the iceberg, according to Diaz.

“I see her winning Grand Slams and becoming world No. 1,” said Diaz.

“People compare her to Serena Williams but she always says: ‘I don’t want to be the next Serena, I want to be the first Coco’. She will determine her own path, that’s for sure. I see her winning Grand Slams within the next two or three years.

“As I said, I knew she was going to be a great player, but the speed of how well she is improving is amazing. It is incredible to see her maturity and how she is handling the pressure.

“The way she handles herself makes me very proud. She is very gracious and very humble. To this day, when she sees me, she greets me – nothing has changed. The big tournaments haven’t changed her. She is still very hard-working also and that is one of the great things about her.”

Diaz is again captaining the USA girls’ team in Prostejov and her current batch of juniors have made a blistering start to their 2019 ITF World Junior Tennis Finals campaign, winning all three of their group matches to set up a quarter-final clash with Japan.

Clervie Ngounoue is the team’s No. 1 player and Diaz is happy to draw comparisons between the 13-year-old and Gauff. She added: “They have similar traits and there are definite parallels.

“When I brought Coco here in 2017, she was a year younger than the other team members but still playing as No. 1, which is the same with Clervie. They have the same fight inside of them.

“Clervie was 4-1 and 5-3 down today [against the Philippines] but I mentioned a few things to her and she turned the match around and won. I see similar qualities in the two. They are totally different players with different personalities, but both great in their own way.”