Coco Gauff prevailed in an all-American showdown on Tuesday at Roland Garros, defeating 2018 French Open finalist Sloane Stephens 7-5, 6-2 to reach her first Grand Slam semifinal.

Seeded No.18, 18-year-old Gauff took 90 minutes to oust 2017 US Open champion Stephens. Gauff avenged her straight-sets loss to Stephens in their only previous meeting, at last year’s US Open.

Gauff has yet to drop a set in the tournament, and has not been pushed beyond an hour and a half in each of her five wins.

"It's important that you have high hopes for yourself, but also, at the same time, it's important to be in reality and I think that's where I am," Gauff said afterward. "I'm in reality where I'm enjoying the moment and enjoying the situation."

Roland Garros rematch to come: Gauff will face another first-time major semifinalist on Thursday when she takes on unseeded Italian Martina Trevisan for a spot in the Roland Garros final. Trevisan ousted Leylah Fernandez earlier on Tuesday, winning her 10th straight match in the process.

In their only prior encounter, Trevisan shocked Gauff in the second round at Roland Garros two years ago, en route to the Italian's breakthrough quarterfinal showing as a qualifier. 

"I remember that match pretty clearly," Gauff said. "I think I was in double digits with double faults. I'm not going to do that this time around. And also, she's a tricky player to play on clay, a tricky lefty. ... I think we're both playing free tennis, and I think that's going to be a good matchup."

All-American affair: Stephens came into Roland Garros 0-4 on clay this season, but as she has done throughout her career, she leveled up her game at a major, especially in Paris.

This was Stephens’s third Roland Garros quarterfinal, and she is up to 32 match-wins at the French Open, which is her highest total of victories at any of the Grand Slams.

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However, Gauff has started her own record of excellence at the majors. By returning to the quarterfinals after her run to that round last year, Gauff became the first woman to reach multiple Grand Slam quarterfinals before turning 19 since Nicole Vaidisova in 2007.

Gauff went one step further this time around. Her current five-match winning streak is her best run since she won nine in a row during last year's clay season by winning the Parma title and reaching the Roland Garros quarterfinals, where she fell to eventual champion Barbora Krejcikova.

"I feel like last year I was looking at the finish line, and now I'm not looking at anything really except that ball in front of me," Gauff said.

Tale of the match: Gauff excelled returning the Stephens second serve, where she won 11 of 13 points (85 percent). Gauff used her dominance there to convert six of her 10 break points, while Stephens went 3-for-9 on her break chances.

Gauff set the tone early by taking charge in lengthy points, quickly breaking Stephens in the second game behind rally forehands. However, when Gauff served for the set at 5-3, Stephens refused to miss and grabbed control, pulling back on serve.

Gauff, though, reclaimed momentum at 6-5, reaching triple set point after using outstanding defense to draw a swing volley error from Stephens. Two points later, Gauff clinched the set with a backhand winner.

Gauff dropped serve in the opening game of the second set but went on a five-game tear after that to serve for the match at 5-1. Two double faults in that game contributed to a service break, but Gauff claimed the win in the following game with a routine break.