Manchester United have booked their spot in the fifth round of the FA Cup following a 3-1 win at Championship side Derby County in their fourth-round match at the iPro Stadium on Friday.

George Thorne cancelled out a Wayne Rooney strike to leave the two teams level at the break, but second-half goals from Daley Blind and Juan Mata saw Louis van Gaal's side advance into the next round.

Man United made a bright start and had a good chance to open the scoring inside three minutes when Rooney cleverly set up Anthony Martial inside the Derby box, but the Frenchman could only curl his effort over the crossbar.

Cyrus Christie had Derby's first sight of goal in the 12th minute, but the full-back fired straight at David de Gea.

The visitors were ahead in the 16th minute, however, when Rooney collected a pass from Martial, before working a yard and bending one into the top corner to cap what was an impressive start for the Red Devils.

Derby had another half-chance in the 22nd minute when Nick Blackman rose above Guillermo Varela at the far post, but the forward could only head into the arms of the waiting De Gea.

A beautiful passing move involving Mata, Rooney and Martial created another chance for the latter 10 minutes before the break, but the Frenchman took one touch too many and Scott Carson smothered the ball.

It was Derby that scored the game's next goal, however, with 23-year-old midfielder Thorne poking the ball past De Gea from close range after a rare venture up the field.

Martial then set up Rooney as Man United came close to regaining the lead late in the first half, but Stephen Warnock came from nowhere to clear with a goal-saving challenge, before Blackman fired just wide down the other end.

Derby had two half-chances early in the second period, but Tom Ince just failed to meet a cross from Christie, before Blackman curled wide of the post from a wide position.

Martial remained Man United's main threat and again set up Rooney inside the Derby box, but the striker's effort was blocked during an end-to-end period of the match at the iPro Stadium.

Mata was next to come close for the visitors just before the hour, but the Spaniard headed a Jesse Lingard cross wide of Carson's post, before the Derby stopper kept out a header from Marouane Fellaini.

Man United were back ahead in the 65th minute, however, when Blind, who somehow found himself inside the Derby box, placed a Lingard cross into the bottom corner.

Derby continued to commit players forward as the match entered its latter stages, but Jacob Butterfield could not release a strike after a quick counter, while Man United remained a threat down the left through Martial.

Indeed it was through Martial that Man United made sure of the victory late on as the France international again beat his full-back before finding Mata, who in turn found the bottom corner to send the visitors into the next round and ease the pressure on the under-fire Van Gaal.