Manchester United fans will always have bad memories of March 5, 2013.
After drawing 1-1 with Real Madrid in their Champions League last-16 first leg, United welcomed Los Blancos to Old Trafford looking for a spot in the quarter-finals.
It was going so well for United.
The Red Devils looked on course for a place in the last-eight when Sergio Ramos put the ball in his own net.
However, the game would transform due to a controversial red card given to Nani.
The Portuguese forward had eyes only for the ball when he made contact with Alvaro Arbeloa.
It was a high challenge but one that he had no intention in making.
However, he was shown a red card, leaving Sir Alex Ferguson and United's players incensed.
United couldn't hold on, with goals from Luka Modric and Cristiano Ronaldo sending the Spanish giants through.
A video remembering the incident has gone viral and United fans are still raging.
View some of the reaction from United fans below...
That season was Ferguson's last chance to win another Champions League title.
He refused to do his post-match interview in the knowledge he was too angry at the referee.
Despite outrage from United fans, Roy Keane actually believed the decision to give a red card was the right one.
"I think the referee has actually made the right call. Everyone's upset about it and it's slightly unlucky, but it's dangerous play," he said on ITV, per the BBC.
"Whether he meant it or not is irrelevant. It's dangerous play - it's a red card. You have to be aware of other players on the pitch. Does he think he's going to have 20 yards to himself?
"Whether it's [a brave decision] or not, it's the right decision. Whether he meant it or not doesn't matter. Nani's a quick boy to go down anyway. He's not the bravest player on the planet."
Madrid managed to make the semi-finals but they were beaten by Jurgen Klopp's Dortmund.