Tennys Sandgren was in no mood to look on the bright side after he came desperately close to dumping No.3 seed Roger Federer out of the Australian Open in a five-set quarter-final thriller.

The unseeded American was physically and emotionally exhausted after he failed to convert seven match points.

The resurgent Swiss champion dramatically sealed his semi-final spot with a 6-3 2-6 2-6 7-6 (10-8) 6-3 triumph in three hours and 31 minutes on Tuesday.

“I’m not encouraged right now … I have zero encouragement,” the world No.100 said.

“I’m sure I’ll look back in a couple days and appreciate the tennis I played the last eight or nine days, but currently I’m just disappointed.”

Sandgren will no doubt replay in his mind the seven opportunities he had to advance to his first-ever grand slam semi-final many more times having started the post-mortem soon after he left Rod Laver Arena.

“Obviously he played them well … I could have played them better,” he said.

“I’ve run through them a bunch of times.

“… You play it as it comes. I thought I did that. I’m sure I could have played them better, at least some of the moments better. But I didn’t, so here I am.”

Sandgren, who reached a quarter-final at Melbourne Park in 2018, had to deal with a bizarre incident at a crucial stage of the match.

With a tense fourth set tiebreak locked at 3-3, a ballkid ran into his leg at the changeover, with the American taking time to walk off the blow.

“That was physically painful,” he said.

“She was apologetic and everything. Accidents happen, so that wasn’t a big deal.

“I’ve had to deal with plenty of things going on in my career.

“This wasn’t anything more or less than what I was accustomed to. I don’t think there was anything that was taking away from my level of play.”