Coco Gauff reached her first Grand Slam semi-final at the French Open on Tuesday when she defeated fellow American Sloane Stephens.
Gauff, 18 years old and ranked 23 in the world, triumphed 7-5, 6-2.
She will face Italy's 59th-ranked Martina Trevisan for a place in Saturday's championship match.
Victory avenged her defeat to Stephens at the US Open and helped erase the memory of her quarter-final defeat last year to eventual champion Barbora Krejcikova in Paris.
"I feel so happy," said Gauff. "Last year was a tough loss for me but I believe that match made me stronger.
"Last time I played Sloane I lost. Today was different. I stayed mentally strong as she is the kind of player who can make shots others can't do."
On Tuesday, Gauff broke in the second game of the match to lead 3-0 before 2018 runner-up Stephens levelled with a break and hold for 5-5.
However, clean, precise hitting allowed Gauff to dominate the 12th game to clinch the opener.
Stephens, playing in her first Slam quarter-final in three years, and Gauff traded breaks at the start of the second set before the teenager again pounced for 3-1.
Gauff held for 5-1, was broken for 5-2 before Stephens dropped serve for the fourth time in the set to hand her compatriot victory.
Gauff was junior champion at Roland Garros in 2018 and then burst into the public consciousness when just 15, she became the youngest woman to qualify for Wimbledon.
Her profile rocketed when she went all the way to the fourth round at the All England Club, knocking out Venus Williams on the way.
While in the French capital, Gauff has graduated high school, marking the occasion on Instagram with a family photo in front of the Eiffel Tower.
"Getting my diploma meant a lot to me," she said Tuesday.
"Lots of players think tennis is the most important thing and it's not."
Italy's Martina Trevisan also reached her first Grand Slam semi-final with a straight sets win over Canada's Leylah Fernandez.
World number 59 Trevisan downed the 17th seeded Canadian, a fellow left-hander, 6-2, 6-7 (3/7), 6-3.
The 28-year-old will face either Coco Gauff for a place in the final.
Trevisan was a shock quarter-finalist at Roland Garros as a qualifier in 2020.
Despite her lowly ranking this year, she returned to the tournament with a maiden WTA title under her belt in Rabat and went into Tuesday's tie on a nine-match winning streak.
She made that 10 when she claimed victory on a second match point having wasted one in the second set.
"I was very nervous on that first match point, I thought I was already in the semi-final," said Trevisan, the first Italian woman to make the last four since Sara Errani in 2013.
"That's normal so I readjusted. I came here from Rabat with a lot of energy. It was my first title and it was a very emotional moment for me."
Trevisan said Grand Slam titles by fellow Italians Francesca Schiavone in Paris in 2010 and Flavia Pennetta at the 2015 US Open were her influences. "They are happy for me. I saw them yesterday as they are in Paris playing the legends event. They are my biggest inspirations."
