Out of form this season, and trying to avoid dropping out of the world’s top 200, Evans battled valiantly in sweltering conditions.

He appeared to be running out of steam as Khachanov threatened to move 5-0 ahead in the decider, but held off three break points and reduced the deficit to 4-3.

Evans fed off the support of a raucous crowd to earn a victory which will live long in the memory.

“I felt a little sorry for myself, but got myself going because I didn’t want to go out of another Slam without a fight and with a whimper,” said Evans after the victory, which was his first at a major this year.

“I could see he was struggling a bit and tried to grab a game at a time.”

Each set was a battle of attrition with lengthy games and multiple break opportunities, all lasting over an hour:

With both players gasping for breath, Evans secured victory in a match which surpassed the previous US Open record – set by Stefan Edberg and Michael Chang in the 1992 semi-finals – by nine minutes.

Evans has endured a chastening year, having won just four ATP Tour matches going into the final Grand Slam of the season.

That dire form, combined with the decision not to defend the title – and ranking points – he won in Washington last year in order to play doubles with the retiring Andy Murray at the Olympics, caused Evans to plummet out of the world’s top 175.

Beating Khachanov is a reward for his perseverance – and his generosity to Murray.

“I’ve had a horrible year. I knew I had put the work in but not enough because I was a bit hurt,” Evans added.

“I like to think I got a bit of luck at the end [against Khachanov]. I nearly blew it but I’m really happy.

“It was amazing at 4-2, it really started to get going. I don’t know how many Brits were there, but it seemed like the whole place wanted me to win.”

Evans has around 48 hours to recover before playing Argentina’s Mariano Navone in the second round on Thursday.