Juan Martin del Potro, spurred on by noisy supporters after two days of illness, saved two match points Monday to outlast Dominic Thiem in a five-set thriller and reach the US Open quarter-finals.

The 28-year-old Argentine 24th seed rallied past Austrian sixth seed Thiem 1-6, 2-6, 6-1, 7-6(1), 6-4 in an emotional fightback for only his second career victory after falling two sets down.

Supporters wearing Argentina football jerseys and chanting “Ole, Ole, Ole” urged on their weary hero from the brink to a stunning endurance-test triumph, creating a Davis Cup-like atmosphere.

“Oh my God,” Del Potro told the crowd. “I was sick the last two days. I came here trying to play the best I can and then when I see this crowd cheering for me, I was trying to play better every game.

“I think I fight like this because of you guys so thank you very much.”

In Spanish, 2009 US Open champion Del Potro told his fans he would never forget their inspirational impact.

“Good night to everybody and thank you very much from the heart for the support you gave me,” Del Potro said. “Was very useful to not to abandon, not to give up, and this match I will always remember.”

Theim said his game was not thrown off by the passionate support for Del Potro.

“It was a great atmosphere. We’re not playing every day in an atmosphere like this,” Thiem said. “I was enjoying it actually that the crowd was not unfair.

“The crowd didn’t affect the result of this match. It didn’t affect me at all. I was really pumped to play in front of a packed Grandstand.”

Del Potro will next face 19-time Grand Slam champion Roger Federer.

Del Potro defeated Federer in a five-set final eight years ago on the New York hardcourts for his only Grand Slam title.

“I have the chance to play Roger again in this tournament, which is special for me,” Del Potro said, adding, “I would like to have the trophy after these matches.”

Asked what he might do to recover for his Wednesday battle for a semi-final berth, the South American replied, “I think it’s a nap for me.”

Thiem enjoyed the intensity of the crowd as the match unfolded, his early dominance followed by a furious fightback from a player who has been nagged by wrist injuries over the years.

“Of course the crowd was on his side,” Thiem said. “I expected it because it’s everywhere like this for him.

“I’m sure there were many Argentinians in the crowd and some different reasons, for his success and he has come back from injuries and his game is attractive. No wonder people like him.”

Even before momentum turned against him, Thiem knew his big lead was unlikely to hold to the finish.

“I knew it’s not going to go all the way like this. If he felt really bad he would have retired,” Thiem said.

“I knew I had to go all the way. It was a great match set four and set five, obviously for the better end for him.”