The match started just about as one might have expected, with Manchester United well on top. Javier Hernandez and Danny Welbeck both nearly got on the scoresheet in the early goal only for both strikers to have their shots blocked by Adrian Mariappa before Antonio Valencia headed well over.
But despite the opening spell looking like the prelude to a comprehensive United victory, the tide turned a little after a collision between Noel Hunt and Nemanja Vidic, which saw both temporarily removed from the field for treatment and the former leaking blood all over himself for most of the rest of the match. Reading were able to assert themselves and managed to trouble David de Gea several times through set pieces.
The hosts weren't looking particularly adventurous, but they still came very close to taking the lead when Adam Federici parried Tom Cleverley's long-range drive straight into the path of an unmarked Ashley Young, who was presented with an easy finish into a more or less unguarded net. Instead of taking it, he shot straight at the goalkeeper, who was able to shove his effort wide.
There was bad news on the injury front for United as well. Phil Jones went in late and off-balance on an attempted tackle of Jobi McAnuff, and ended up jarring his ankle so badly that the right back was forced off the pitch, replaced by Nani as Valencia dropped back into the defence. Nani made an immediate impact, crashing a volley off the base of Federici's far post within minutes of his introduction.
Better was to come, but it would take until the second half to do so. Just after the hour mark, Valencia was able to find Nani in the box as the Reading defence went missing, and the winger dispatched his effort past Federici to give United a vital lead.
Although the visitors responded well, with Adam le Fondre forcing de Gea into a superb stop after a twisting snapshot, Chicharito would double United's tally mere minutes thereafter. This time, Nani turned provider, whipping in a cross from the right with the Mexican got a head to, leaving Federici with no chance.
Again, Reading looked for a reply and this time they got it. Chris Smalling managed to intercept a dangerous looking pass intended for le Fondre, but he didn't do well enough when he tried to knock the delivery to safety. Instead, he simply presented possession to McAnuff, who slotted home coolly from close range to make it 2-1 in the 81st minute.
The visitors flooded forward in search of the equaliser, leaving the last ten minutes of match incredibly open. United had their chances to make it 3-1, but ultimately didn't need to worry about wasting them -- although their defending left rather a lot to be desired. After four minutes of somewhat-panicked injury time, Reading were defeated, and now a probable quarterfinal date with Chelsea awaits.