There was never much doubt in Frances Tiafoe’s mind that this is where he belongs. The setbacks and disappointments of close Grand Slam losses have only served as an affirmation to himself that he can compete with the best on the ATP World Tour.

Since turning pro in 2015, the tennis prodigy from Hyattsville, Md., has received a Grand Slam main draw wild card on three separate occasions, only to lose in the first round each time.

But at this year’s Australian Open, Tiafoe earned another chance by qualifying for the main draw and delivered a signature win, beating 98th-ranked Mikhail Kukushkin of Kazakhstan, 6-1, 6-7 (7-3), 6-3, 6-2, on Tuesday for his first victory in a Grand Slam match.

“I know in the back of my head I have a Grand Slam win, which definitely takes a lot off of me, a big load off,” said Tiafoe, who turns 19 on Friday. “I feel pretty comfortable now.”

Tiafoe’s confidence was bolstered by a loss late last year. Playing against 20th-ranked John Isner at the U.S. Open in late August, Tiafoe earned a match point before losing to his more experienced opponent in five sets.

Instead of dwelling on the loss, Tiafoe was encouraged.

“I learned a lot,” he said. “I learned that I could definitely play at a really high level and I definitely belong at this level. I’m not shying away from competing with these guys or thinking I’m not ready for this, because I’m definitely ready for this level. I just got to keep competing and keep believing.”

Ranked No. 108 in the world, Tiafoe is part of a group of teenage hopefuls who are tasked with reviving men’s tennis in the United States. Not since Andy Roddick lifted the 2003 U.S. Open trophy has an American won a men’s Grand Slam singles title, and U.S. tennis fans have been yearning to crown a homegrown hero.

It may take some time, but Tiafoe believes they’re ready for the job.

“I mean, we’re definitely coming,” he said. “There’s a really good crop of us, and we’re all working really hard and trying to get American tennis to where it should be and where it always has been, and that’s at the top of the game. We’re working all our hardest, and soon we’re surely be there.”

The steady progression from highly touted junior player to a pro hovering near the top 100 in the world has Tiafoe feeling confident about where he is in his career. This past fall, Tiafoe enlisted the help of former top-15 player Robby Ginepri, and the improvement in his game was on full display during his first-round victory in Melbourne.

Later this week, Tiafoe will face Germany’s Alexander Zverev, a 19-year-old ranked No. 24 in the world, in the second round. The two have never played each other on the pro tour, but Tiafoe expects a “fun match to watch” against his good friend from the junior circuit — one featuring two up-and-comers in tennis.

“I’m pretty happy with my progression so far and hopefully can keep it going,” Tiafoe said. “It feels good that I’m doing this well.”