QPR boss Mark Warburton was left stunned by the offside call which cost his side a place in the quarter-finals of the Carabao Cup.
Charlie Austin was penalised despite seeming to be a good yard onside when he tucked away what looked like the winner against Sunderland with nine minutes remaining.
Albert Adomah's shot was deflected into the path of Austin with defender Dennis Cirkin playing both onside, but as the veteran striker bundled the ball home a flag was belatedly raised.
With no VAR in operation, penalties beckoned and League One Sunderland duly won the shoot-out 3-1 following a goalless draw.
"I've just seen it. What can I say without getting fined?" fumed Warburton.
"It's staggering to be that wrong on a major decision in a game of that importance. I was told it was immediately offside by the fourth official.
"Having just seen the picture I've just seen, wow! It's an appalling decision which has cost the club in all sorts of ways.
"The picture I've just seen, we're not talking about an inch or a marginal decision. It's feet, between Charlie being onside and offside. Those types of decisions, you cannot get it wrong.
"With what's at stake, the financial implications for the club, big crowds home and away, everything which comes with progression to the last eight, I've never been so shocked to see a picture like that.
"To be that far onside, you have to question what did they see? I hope this doesn't get me too much of a fine."
Austin's agony was compounded when Black Cats keeper Lee Burge saved his penalty, the first in the shoot-out.
He was not the only culprit, though, with Ilias Chair and Yoann Barbet skying their penalties and denying Rangers a place in the last eight for the first time since 1988.
A club with an abysmal record in the cups, they have now been dumped out of this competition by League One opposition in each of the last four seasons.
Warburton's men will look to bounce back when they host Nottingham Forest in the Championship on Friday (7.45pm).
Meanwhile, Sunderland boss Lee Johnson said: "I thought bar a 20-minute spell in the first half we were worth the draw and the victory. In the second half we were the better side.
"It's a really good learning game for us and the atmosphere was unbelievable. I think our goalkeeper Lee Burge deserves a lot of plaudits tonight.
"I think this was our biggest test to date. It shows we've got spirit in the club."
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