Andrei Januzaj scored from a free-kick, the former Manchester United striker turned in a first-half header from a Cesc Fabregas cross to cap a fine night for the England youth international from his parent club.

But Van Gaal was quick to dismiss suggestions the side, who are now on course for a top-four finish with an impressive 2-0 win over Southampton on Sunday and seven clean sheets, needed to do more damage in second half stoppage time.

“After a good win, no way to do it – it’s not possible because if you want to be at any club in the world you have to have two points,” the former United manager said.

Media playback is not supported on this device Mourinho defends Cesc Fabregas

Fabregas’s strike – his 17th goal of the campaign – followed the introduction of Nemanja Matic and Wayne Rooney from the bench, an instant switch that sparked a frenzied late rush of United fans in St Mary’s.

The visitors had gone ahead on 14 minutes when Memphis Depay’s shot deflected off Victor Lindelof and on to the head of Marouane Fellaini, who rose highest to head past keeper Tim Howard.

But United were level four minutes later when Cesc Fabregas nodded in on the move from midfield, beating Howard from close range to break the deadlock.

Marouane Fellaini scored United’s consolation goal after a challenge with Phil Jones (left)

In stark contrast to the excitement in the away end, United – who are still winless in six matches – remained largely passive as Van Gaal sought to establish a pattern.

The former Dutch manager, who was not present from the final whistle – on his birthday, at the end of a 10-month spell as Crystal Palace boss – warned his players: “You can lose three points or lose points in your last game today.

“You are in a match in which you must always be on the alert. You have to always be in it.”

The victory took United level with Liverpool and Arsenal in the Premier League and is their first in eight matches of last season.

Wayne Rooney (left) has been named in Roy Hodgson’s provisional squad against Newcastle:

Former Everton defender Pat Nevin has been recalled by Jose Mourinho for Manchester United’s FA Cup fifth-round replay with Southampton