US Open champion Dominic Thiem said he was not a “machine” and simply had a “real bad day” in stumbling out of the Australian Open to Grigor Dimitrov Sunday.

The Austrian third seed, a finalist last year, was shocked 6-4, 6-4, 6-0 by the Bulgarian to miss out of a place in the quarter-finals.

He admitted to dealing with “some little physical issues”, but didn’t want to elaborate, insisting: “I don’t want to find any excuses.

“But the thing is that I’m also not a machine,” he added. “I mean, sometimes I would like to be, but there are really, really bad days. As soon as you’re not a hundred percent there on the court on this level, then results like this come up, and that’s exactly what happened today.”

World No 3 Thiem went through a draining five-set epic to beat Nick Kyrgios in front of a raucous crowd on Friday, but said it didn’t affect the way he played against Dimitrov.

“I mean, it was a special match two nights ago, and of course I woke up maybe a little bit different than on a normal match, especially with all the energy from the crowd,” he said.

“But from that side, it didn’t really affect me today.”

Thiem simply struggled to match the intensity of the Bulgarian, who won seven of 15 break points compared to the Austrian’s two from seven.

“I think since probably 10 years or a little bit less, he’s one of the best players on tour. If he’s on, he’s super tough to play,” Thiem said.

“I really wish that he can make a great breakthrough at a Grand Slam. He would definitely deserve it.

“As I said, I was not on a hundred percent today, and it doesn’t matter if it’s Grigor or anybody else, everybody is way too good that I beat them if I’m not 100 percent.”

Dimitrov, who made the semi-finals at Melbourne Park in 2017, will play Russian qualifier Aslan Karatsev for a place in the last four on Tuesday.