New York, NY, USA, 30 August 2016 | AAP

Australian youngster Jordan Thompson was inconsolable after suffering through a gut-wrenching five-set defeat on his US Open debut at Flushing Meadows.

The 22-year-old blew a two-set advantage and two match points in a brutal 5-7 3-6 7-6(5) 6-4 7-5 loss to Belgian Steve Darcis on Monday.

Playing in sickening heat he compared to “something like Vietnam or Bangkok”, Thompson cramped up in the final game of the four-hour, 11-minute epic on the old Grandstand Court.

“It’s hot, humid, the sun’s out, there’s no shade. I was hurting in that last game. No doubt I struggled a bit at the end,” Thompson said.

The world No.92 served for the match at 5-4 in the third set and watched Darcis save one match point with an audacious volley pass from the baseline.

“I just felt like I left myself down, let other people down. It’s not good,” Thompson said.

“Just the people in the box there supporting me, I’ve worked with those people for a long time and it’s what you work towards – to be playing here and winning matches and I let it slip away.

“So it’s just a bitter disappointment.”

As if the loss wasn’t tough enough to digest, Thompson had to sit through drug testing afterwards, but said it was all another big learning experience.

“Everything’s a learning curve at this age,” he said before turning his attention to the Asian swing.

“I’ll have to regroup for those.”