A highly questionable red card given to Manchester United's Nani in the 56th minute for all intents and purposes ended the Red Devils' Champions League run. Real Madrid will advance to the quarterfinals after a 2-1 win on Tuesday gave them a 3-2 win in aggregate.
At the time of the red card, Manchester United led Real Madrid 1-0 while playing at Old Trafford in the second leg of their final-16 Champions League match. 
This gave them a 2-1 lead in aggregate, and cast them in a favorable position. 
Then, Nani drew the card after contesting a high ball with Alvaro Arbeloa. There was slight contact, but a red card was a gross overreaction. The crowd instantly went nuts, and the card was baffling enough that it even drew Sir Alex Ferguson out of his dugout.
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Trying to capitalize on the man-up advantage, Jose Mourinho sent in the maligned Luka Modric, and it worked. 
In the 66th minute, Modric drilled a beautiful bender from 25 yards out to glance off the post and in for goal. 
Modric then came up big as he made a nice center pass to break down the defense and led to Gonzalo Higuain sending a cross to the sliding Cristiano Ronaldo, who netted the goal. 
This gave Real a 2-1 lead, and it meant that Manchester United were going to have to score at least two goals to advance. Down a man, that was way too much to ask. 
It is too bad that this match will largely be remembered for the red card. It was an entertaining and well-played affair, and it was interesting before it even started. In a shocking move, Sir Alex Ferguson kept Wayne Rooney out of the starting lineup. 
Rooney entered in the second half, and narrowly missed a chance on goal in the 84th minute, but at that point, this one was all but over. 
Prior to the red card, the move was working out well for Ferguson. Knowing that if they shut out Real they would advance, Manchester United played a nice defensive first half as the two entered halftime scoreless. 
In that half, Manchester United were getting the better chances and looked like the more aggressive team. It's all for naught, though—their Champions League campaign is over. 

Player Grades
Robin van Persie: C
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Robin van Persie was active, but he just wasn't very effective. He botched a relatively easy chance in the second half and couldn't make anything happen.

David de Gea: B+
Real Madrid's two goals were not David de Gea's fault.
He was well positioned in this match, and he made several nice saves on the day.

Cristiano Ronaldo: A-
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Ronaldo just keeps piling goals in big moments, and this match was no different. His sense of timing was on full display as he slid in to deliver the cross for the goal that essentially ended this match.
Ronaldo was active all game. While he had a quiet first half, he helped keep the pressure on Manchester United in the second.