Manchester United 4 AZ Alkmaar 0

Ole Gunnar Solskjaer made nine changes to the side that defeated Manchester City in their own backyard last weekend, and just three players – Axel Tuanzebe, James Garner (making his first Old Trafford start) and Greenwood – remained from the starting XI that began matchday five against Astana.

There was plenty of attacking dynamite packed in United’s forward line, however, with Anthony Martial supported by Mata and Greenwood. But the proactive visitors made the brighter impression in the opening stages; left winger Idrissi symbolising Alkmaar’s early confidence with a flamboyant rabona pass and a bright strike at Sergio Romero’s goal.

Five minutes later, the playmaker came closer; the Reds were set free inside the United half by another incisive Greenwood pass, and Young’s low centre enabled Mata to fire goalwards, only for his shot to be blocked by former Southampton midfielder Jordy Clasie.

Those moments came in the midst of a decent 10-minute spell for United, but then Idrissi whipped one across the six-yard box that a supplementary touch would have converted into a Dutch lead and then, minutes before the interval, this time from the right, Svensson’s cross was turned over by the stretching De Wit. It was an appropriate end to a scratchy, nervy half for Solskjaer’s boys.

Martial fired over from Greenwood’s clever cutback just after the restart and then, from figuratively nowhere, the Reds found the breakthrough.

Andreas appeared stranded and hemmed in by two AZ players by the Stretford End’s left-wing corner flag but with an ingenious bit of technical wizardry managed to free the ball to Mata. His low delivery across the goalmouth found no red shirts in the vicinity, but Young, closing in on the right, found the net with laser-guided accuracy from what appeared to be a near-impossible angle.

What wonders confidence can work. Minutes later, Garner snapped in to win the ball 20 yards from goal, and the ball rebounded to Greenwood – comfortably the best player in red on the night. His quickly released shot was past Bizot before the keeper could get down to reach it.

Martial departed to be replaced by Chong, and within minutes it was 3-0, and then 4-0. First Greenwood was checked by Clasie in the box, and Mata stroked home from the spot, and then Greenwood himself fired home from the right of the penalty area; his two goals were rich reward for a display full of promise and intelligence.

Solskjaer then rang the changes, as Young and Maguire headed off, for Ethan Laird and Phil Jones respectively.

A neat tip over the bar from former AZ man Romero denied Alkmaar’s Stengs a consolation goal, but United could also have added to the tally, with Greenwood a roving threat – though the wunderkind struck a rare duff note with a wild shot in the final five minutes.

But despite the nerves during the first period, it was a pleasing night, all things considered, come the final whistle. United headed for the last 32 buoyed by the team's biggest victory since the opening day of the season, and a third consecutive success in all competitions.

MATCH DETAILS

United: Romero; Young (c, Laird 68), Tuanzebe, Maguire (Jones 68), Williams; Garner, Matic, Andreas; Mata, Martial (Chong 59), Greenwood.

Subs not used: Grant, Fred, McTominay, Rashford.

Goals: Young 53, Greenwood 58, 64, Mata 62.

Bookings: Laird.

Alkmaar: Bizot; Svensson, Clasie, Wuytens, Wijndal; Midtsjo, Stengs, Koopmeiners (c); Sugawara (Vlaar 68), De Wit (Druijf 63), Idrissi (Ouwejan 77).

Subs not used: De Boer, Aboukhlal, Reijnders, Kramer.

Bookings: Clasie, Midtsjo, Koopmeiners.

Attendance: 65,773.