Manchester United crashed out of the Champions League in controversial circumstances after Real Madrid recorded a 2-1 victory - and 3-2 aggregate win - at Old Trafford on Tuesday evening.
With the whole football world tuning in, to watch two of the biggest clubs on the planet go head-to-head for a place in the quarter finals of Europe's elite club competition, a single refereeing decision midway through the second half turned the tie completely on its head.
The red card shown to Portuguese winger Nani ruined the spectacle for everyone, leaving neutral supporters short-changed from what was turning out to be a titanic battle, after Sir Alex Ferguson's side had taken a slender 1-0 lead on the night, and 2-1 aggregate advantage.

Then, in the 56th minute, Nani was sent off after raising his foot high and connecting with the ribs of Real Madrid defender Alvaro Arbeloa as Manchester United broke free from a corner.
Turkish referee Cuneyt Cakir's decision to reprimand the attacking midfielder with the harshest of punishments, prompted a furious remonstration from Ferguson on the touchline, and the Old Trafford crowd became equally vociferous in airing the collective feeling of discontent.
Real Madrid took control against ten-men, scoring two goals in quick succession, with substitute Luka Modric and returning hero Cristiano Ronaldo putting the final nail in Manchester United's coffin.
The Premier League leaders rallied in the closing stages, but could not complete a fight back - even after the introduction of Wayne Rooney - with the two earlier strikes enough to settle the tie, leaving home fans to ponder what might have been had it not been for the controversial decision.
Unfortunately, it's not the first time that a referee has been the major talking point in a high-profile football match. But where does last night's calamity rank amongst GiveMeFootball's list of the five worst red card decisions ever? Find out here…

Vincent Kompany | Manchester City

Manchester United fans shouldn't feel too sorry for themselves after last night's controversy, because good fortune often favours them when it comes to questionable red card decisions.
Take, Vincent Kompany's sending off for Manchester City in their 1-0 FA Cup third round defeat on January 8, 2012. Nani was at the centre of the incident again, but this time on the receiving end of the tackle in question, which came in the 12th minute of the game, soon after Wayne Rooney had given United a valuable lead.
Kompany's withdrawal effectively ended any hope Roberto Mancini's side had of coming back into the game, leaving the Citizens with over 75 minutes to play with ten men.

Robin van Persie | Arsenal

Another Champions League controversy came when former Arsenal striker Robin van Persie was sent off after receiving a second yellow card in Camp Nou in their last-16 second leg tie on March 9, 2011, for kicking the ball away after play had already been stopped.
Arsene Wenger was furious with Swiss referee, Massimo Busacca, claiming that the sending off "killed the game", and was the key reason for the Gunners' exit.
"I think two kinds of people can be unhappy: those who love Arsenal and those who love football can be frustrated with the referee's decision because it's very difficult to understand his attitude," reflected the Frenchman after the game. "How can you kill a football game like that? It was a very promising game, very interesting, that's the regret."

Eden Hazard | Chelsea

Only last month, Chelsea winger Eden Hazard was sent off in extraordinary circumstances in the club's Capital One Cup semi-final second leg defeat against Swansea at the Liberty Stadium, after he was adjudged to have kicked a ballboy whilst trying to retrieve the football.
After a 2-0 defeat at Stamford Bridge in the first leg, the Belgian star let his frustration get the better of him with the game still goalless in the 78th minute. As the ball drifted out for a Swans goal-kick, the ballboy's obvious attempt to delay the game's restart, prompted an altercation, which resulted in an early bath for the Blues ace.
"The boy put his whole body on to the ball and I was just trying to kick the ball," explained Hazard in the days after the game. "I think I kicked the ball and not the boy. I apologise.
"The ballboy came in the changing room and we had a quick chat and I apologised and the boy apologised as well. It is over. Sorry."

Peter Crouch | Tottenham Hotspur

After knocking out Inter Milan in the previous round, Tottenham's hopes of Champions League glory were destroyed as early as the 15th minute of their quarter-final first leg clash against Real Madrid at the Santiago Bernabeu.
Peter Crouch's controversial sending off following two soft yellow cards effectively ended Harry Redknapp's hopes of masterminding another memorable European victory, this time over Jose Mourinho.
The nine-times winners ruthlessly punished the England striker's indiscipline, crushing Spurs 4-0 after he was punished for a quick succession of lunging tackles in the Spanish capital.
Real Madrid travelled to north London completely in control of the tie, and after playing out a 1-0 victory at White Hart Lane progressed to the semi-finals off the back of an emphatic 5-0 aggregate victory.