Just a couple of years ago, a frustrating run of injuries left Jack Draper thinking he "wasn't cut out for tennis."
But on Wednesday, he will have the chance to become the first British man to reach the US Open singles semi-finals since Andy Murray won the title in 2012.
Draper will play Australian 10th seed Alex de Minaur in the quarter-finals from around 19:00 BST, with commentary on BBC Radio 5 Live and the BBC Sport website and app.
Draper, long tipped as one of British tennis' great prospects, will hope this is the start of things to come.
BBC Sport looks at how he can beat De Minaur.
As a 6ft 4in left-hander, Draper's natural tools can give opponents pause for thought before they even step onto court.
Once they get there, they are confronted with a big first serve and an explosive forehand to boot.
The scarcity of left-handers in the game already makes Draper tricky, but the fact that he is naturally right-handed makes him even more difficult to face. Essentially, his double-handed backhand almost becomes a second, powerful forehand.
It also gives him something in common with Rafael Nadal - which is no bad thing.
His serve has been an important weapon throughout the year. He has won 78% of first-serve points on the ATP Tour, second only to Taylor Fritz (78.8%).
Draper has upped that to 80% at Flushing Meadows. It is little wonder he has been broken just once in his four matches so far.
While his power from the baseline is undoubtedly a strength, the 22-year-old is also capable of mixing it up when necessary.
"You look at his game [and] the way it’s developed from the back of the court, both forehand and backhand are so solid," six-time Grand Slam semi-finalist Tim Henman told BBC Radio 5 Live.
"He's not shy of finishing the point at the net, whether that’s behind a serve-and-volley or coming in behind a big forehand."
Draper has yet to drop a set and has not lost more than four games in a set
Only Novak Djokovic (four times) and Andre Agassi have dropped fewer games in making the US Open quarter-finals in the Open Era
The Briton's combined seven hours on court is the least of the quarter-finalists by around an hour and a half
It is only the third time Draper has gone beyond the second round of a major
While Draper has long been touted as Murray's successor, it has not been a straightforward journey.
The former Wimbledon juniors runner-up struggled with hip and shoulder injuries to the point that he considered quitting tennis.
Instead, he battled his way back to full fitness, ultimately becoming British number one in June.
However, he has bigger goals - chiefly becoming "one of the top players in the world".
More recently, Draper admitted to finding it "difficult" to have his integrity questioned after a controversial end to his win over Felix Auger-Aliassime at the Cincinnati Open.
However, he has shown real composure during his New York run, remaining focused on the job at hand, with even his celebrations understated.
"To be able at that age to be so serene about everything that he is doing is showing a lot of maturity," 2013 Wimbledon champion Marion Bartoli told Sky Sports.
His coach James Trotman told BBC Radio 5 Live this is the calmest he has seen Draper at a Slam.
"You start to learn the best-of-five, how you’re going to handle yourself, the emotions, the days off in between," he said.
"I think it’s the progress that we’ve been looking for."
This is unchartered territory for Draper, whose previous best at a major was a fourth-round showing in New York last year.
It will also be the first time the Briton has played on the 23,771-capacity Arthur Ashes Stadium - a venue he has visited every day during his time in the city.
But this has been a breakthrough year for Draper, following up his first ATP Tour title in June with an eye-catching win over Wimbledon champion Alcaraz at Queen's.
He is now at a career-high of 25th in the world rankings.
"He’s managed to have a long period of time where he hasn’t missed months of being on tour, so he’s banking way more experience," Great Britain Davis Cup captain Leon Smith told BBC Sport.
"He’s getting more experience. He’s in the bigger events more often. From that, he’s understanding how better to handle himself."
Quarter-final opponent De Minaur is undoubtedly more experienced. He has nine ATP title to his name and has reached the last eight in three straight Slams.
He also leads the head-to-head, having won all three of his matches against Draper.
But, like Draper, the 25-year-old Aussie has never made it to a major semi-final.
"You're expecting De Minaur to make it awkward and tricky," Bartoli said.
"Jack will need to hit through the court and keep on going at him."
Should Draper beat De Minaur, he could face world number one - and his occasional doubles partner - Jannik Sinner next.
The Italian takes on fifth seed Daniil Medvedev in the quarter-finals in a clash of the last remaining Grand Slam winners in the draw.
As the lowest-ranked player left, Draper will be the underdog for as long as he remains in the tournament - but having got this far, anything is possible.