Fearnley has been making so rapid progress over the past 15 months, it’s easy to forget how his lack of experience has maintained its highest level.
More than a year ago, the former American college student ranked outside of the world's leading 500 players.
He has since been in the top 50 in June after a stunning introduction to the ATP Tour.
Fearnley is used to drawing compelling names in the early days of the Grand Slam and has come over on some of the iconic courts in the game.
But his form has been compromised in recent months due to nerve tension, which has been particularly damaging to his serve.
Fearnley encountered 12 double glitches against Zverev, including one of each service game he lost in the first set.
“It's a problem, I have some obvious loopholes in my game, but I can compete even in poor service.” Fearnley said he needed treatment for a shoulder injury in the first set.
“It’s definitely the problem I’m going to solve – I’m just giving to the molecules.
“I could actually serve for 100 seconds in a row, but it was something to see the lights, see the courts and on the other side of the network, which made it so tricky.
“Sometimes, sometimes it's hard. I'll figure it out eventually.”
The issue also affected his first round defeat of Roberto Bautista Agut, but despite 18 double failures, he was able to get out of the way with Wily Spanish veterans.
This time, Fearnley didn't get the same mistake in one of the best matches in the world.
Beaten 2020 finalist Zverev won the opening ceremony of a single match in the first match, and Fearnley later said the German “stand there” for nearly 15 minutes after being asked to play.
Fearnley also started slowly in the next two sets, but saved some pride after Zverev led 5-1 in the third.
Fearnley managed to extend the game with his ground puncture loosening – marveling the crowd with explosive blows and impressive athleticism – but it was too late.
This is Fearnley's third defeat against Zverev this year, his second loss after another straightforward defeat at the Australian Open.
“I played better overall [than Melbourne]I had some lapses in concentration, but I felt very comfortable there. ” Fearnley said.
In evaluating his U.S. Open overall, he added: “I'm happy with the way I play and the way I compete, and psychologically I think I'm good. I can get a lot from it.”