Australia's last singles hope, John Millman has been bundled out of the US Open.

Millman suffered a straight sets loss to German Philipp Kohlschreiber on Sunday morning AEST, going down 7-5, 6-2, 6-4, in the third round.

It is Millman's best ever finish at the US Open and will see his ranking rise to 180 in the world as he continues his return from a groin injury.

Millman said post-match, despite the loss, he was happy with his run at Flushing Meadows.

“I could walk off the court and say I was a little bit sore or whatever but, at the end of the day, physically I felt really good and I got beat by a guy who just played a little bit better than me," Millman said.

“To be honest, I thought the whole match was pretty high quality.

“I really tried to back myself when the time was there to do so and I have to continue doing that.

“But I really think my game is at a good level right now and this week has been so good for that.”