It turned out to be a comfortable evening for the 11-time FA Cup winners, but it could have been so different for Cambridge had the League Two side not spurned a gilt-edged opportunity in the opening seconds.
Manchester United 3-0 Cambridge United
FA Cup Fourth Round replay
Tuesday 3 February 2015
We will never know. And in the end first-half goals from Juan Mata, Marcos Rojo and a late strike from England U20s international James Wilson were the difference as United cruised to victory.
However, with the game less than a minute old, Daley Blind miscontrolled and Tom Elliot found himself clean through on David De Gea within a minute of the kick-off.
He beat the in-form United stopper, but was cruelly denied by the outside of the post.
At the other end, the 6,500 travelling Cambridge fans had barely taken their seats after congestion around Manchester resulted in kick-off being delayed by 20 minutes.
They had arrived in time to witness Elliot’s miss, just, but did not let it quell the party atmosphere they were determined to enjoy.
“Thank you for our toilets” was the tongue-in-cheek chant from the East Stand as the game got under way, after a local supplier had promised to pay for a refurbishment at The Abbey Stadium should they flush Louis van Gaal’s men out of the Cup.
And for much of the opening exchanges Richard Money’s side, who he had sent out in a bold 4-4-2 formation held their own in front of a near-full Old Trafford.
Almost 20 minutes passed before Chris Dunn was called into action, as Wayne Rooney cut inside from his starting berth on the right flank, and fired straight at the Cambridge stopper from the edge of the box.
Manchester United’s formation has been the subject of much discussion this season, and Van Gaal sprung another surprise by starting England captain as a right-winger in a 4-4-1-1 system, with Marouane Fellaini playing off striker Robin van Persie.
However, it was from the left that United’s first two goals were created.
With Fellaini acting as a target man, Angel Di Maria picked out the Belgium international at the back post.
He met the whipped cross and headed perfectly into the path of Mata, who could not miss from a yard out.
Seven minutes later United doubled their lead. Again Fellaini was at the heart of the action as his shot was blocked.
It fell to Van Persie on the left and with a deft chip of a cross he found Rojo, who glanced home his first goal for the club.
The neutrals would have been fearing a Cambridge capitulation at this point.
As the second half progressed with the home side attacking the Stretford End, the League Two side looked momentarily overwhelmed for the first time in the tie.
Mata, Van Persie and Di Maria (twice) all went close for Van Gaal’s side, but none could find their way past a steadfast Cambridge backline – determined to go out battling.
At the other end substitute Sullay Kaikai did finally get a touch of the ball as he ran at the United goal before blazing high and wide from the edge of the box.
United were comfortable though, and Van Gaal decided to ring the changes.
Wilson replaced van Persie, while Ander Herrera came on for Di Maria.
Wilson put the game well and truly to bed with a fine low left-footed strike from edge of the box as United cruised into the Fifth Round, where they will travel to Deepdale to take on Preston North End on Monday 16 February.
Manchester United (4-4-1-1): 1 David De Gea; 33 Patrick McNair, 12 Chris Smalling, 6 Jonny Evans, 5 Marcos Rojo; 10 Wayne Rooney, 8 Juan Mata, 17 Daley Blind, 7 Angel Di Maria; 31 Marouane Fellaini; 20 Robin van Persie.
Substitutes: 49 James Wilson for Van Persie 66, 21 Ander Herrera for Di Maria 69; 18 Ashley Young for Rojo 80
Substitutes not used: 32 Victor Valdes, 4 Phil Jones, 25 Antonio Valencia, 9 Radamel Falcao.
Goals: Mata 25, Rojo 32, Wilson 73
Cambridge United (4-4-2): 1 Chris Dunn; 2 Richard Tait, 4 Josh Coulson, 18 Michael Nelson, 3 Greg Taylor; 22 Luke Chadwick, 8 Tom Champion, 20 Cameron McGeehan, 7 Ryan Donaldson; 10 Tom Elliott, 15 Robbie Simpson.
Substitutes: 23 Gearoid Morrissey for Chadwick 51, 31 Sullay Kaikai for Simpson 61, 6 Ian Miller for Nelson 86.
Substitutes not used: 13 Will Norris, 19 Dominic Ball, 24 Rory Gaffney, 27 Bobby-Joe Taylor.
Referee: Jonathan Moss.
Video highlights of the Fourth Round replay at Old Trafford