Before the intriguing last-eight encounter got underway, a minute’s silence was held to remember the victims of the shooting in a gay nightclub in Orlando at the weekend, where 49 people lost their lives.

Dempsey gave the host nation the lead with a header midway through the first half before Ecuador’s Antonio Valencia and Jermaine Jones of the US were both given their marching orders after the break.

Manchester United’s Valencia, who had already been booked, hacked down Alejandro Bedoya and was dismissed, with Jones following suit in the aftermath as he appeared to jab Michael Arroyo in the face.

With tensions inside Soldier Field rising, the US went further in front when Dempsey turned provider for Zardes, who tapped home just after the hour mark to move the hosts to the brink of the semi-finals.

The South American outfit ensured it would be a nervy finish for the partisan crowd inside the venue as Arroyo converted a well-worked set-piece 16 minutes from time to halve the deficit.

Ecuador then went in pursuit of an equaliser and they almost found one but Enner Valencia’s header flashed the wrong side of the post.

Deep into stoppage time, the South Americans were inches away from levelling as American John Brooks almost turned the ball into his own net but fortunately saw the ball sail wide.

The US were able to hold on for a momentous win which saw them book a place in the last four of the Copa América for the first time since 1995.

“They are understanding what the next level is all about,” US manager Jurgen Klinsmann said.

“The team performance was outstanding.

“I really hope the country gets behind us for the semi-final.

“The support we have received has been fantastic.

“This is big time.”

Klinsmann’s men will go up against either Argentina, beaten finalists at last year’s tournament, or Venezuela in the semi-finals in Houston on Tuesday (June 21).