Manchester United 3 Colchester 0

The Reds struggled to make in-roads against the League Two side in the opening 45 minutes but, once Marcus Rashford struck the opener, the result was never in any doubt.

An own goal by Ryan Jackson quickly doubled the advantage, and Anthony Martial got in on the act from close range to cap an entertaining spell of football.

As expected the match was played mainly in Colchester’s half with Reds goalkeeper Sergio Romero probably able to ponder on what Christmas presents he had yet to buy.

In earlier rounds, the Essex side knocked out Premier League opposition in Crystal Palace and Spurs on penalties, without scoring in normal time, and it looked like they’d hope to survive for a similar outcome at Old Trafford.

Despite the total domination it was proving a frustrating exercise to break down the League Two outfit and, even when Andreas Pereira twice superbly guided passes into Rashford’s path, the England striker’s touch failed him, as the assistant-referee’s flag stayed down.

It was all about Rashford’s chances, however, and before passing up the Andreas gifts, he had blasted an early free-kick into the midriff of keeper Dean Gerken who spilled the shot but reacted to smother as Juan Mata tried to pounce.

Rashford also hit a rising rocket over the bar but there was precious little to trouble Gerken, for all of the possession.

Colchester did finally manage to get close to disturbing Romero in the 44th minute as Callum Harriott’s shot skidded just wide, even if the Argentinian had it covered. In added-on time in the first half, Martial almost came up with the goods as he hit a hard, swerving shot off target.

John McGreal's side were probably the architects of their own undoing after 51 minutes when they registered their first shot on target, from Jackson, and first save for Romero. But the reprisal was instant.

Romero bowled his clearance out to Nemanja Matic who set Rashford free, with the right-back, for once, out of position. This time, the Mancunian hitman got it all right as he cut inside and smashed in the opener.

He almost had a second as he ghosted in at the far post on Mason Greenwood’s cross, four minutes after his goal, but he was beaten to the connection by Jackson, who nudged the ball into the net off his leg.

There was no stopping United now and, after 61 minutes, Martial made it 3-0. Mata was the source of the goal as he lifted a pass for Rashford and the forward's ball across goal allowed Martial to throw himself in to turn it home.

With a semi-final place effectively secured, Solskjaer brought all his subs on within four minutes of the third goal. Brandon Williams, Jesse Lingard and James Garner came on for Luke Shaw, Rashford and Axel Tuanzebe.

After Mata fired a low shot wide, Harry Maguire was close to scoring his first goal for the club with a header that forced a flying save out of Gerken.

The Reds continued to dominate but were unable to add to the scoreline, with Williams also having an attempt blocked and Greenwood working the space for an opening but sending his drive over the to of the bar, as he looked to extend his run of hitting the net at Old Trafford.

Colchester tried manfully to give their travelling supporters something to cheer but Romero was comfortably able to earn another clean sheet to add to his collection.

The fact the home side had 26 goal attempts, compared to the visitors' five, said it all in the end.

MATCH DETAILS

United: Romero; Young (c), Tuanzebe (Garner 65), Maguire, Shaw (Williams 61); Matic, Andreas; Greenwood, Mata, Rashford (Lingard 61); Martial.
Subs not used: Grant, Jones,  McTominay, Chong.

Goals: Rashford 51, Jackson og 55, Martial 61

Bookings: Young

Colchester: Gerken; Jackson, Bramall, Lapslie, Prosser; Pell (Stevenson 65), Norris, Comley (Gambin 73), Harriott (Poku 77); Eastman, Nouble

Subs not used: Ross, Sowunmi, Brown, Clampin 

Bookings: Pell, Gerken, Harriott

Attendance: 57,559.