On Saturday evening, when Wayne Rooney slid on his knees in front of Manchester United’s travelling support at the Emirates stadium to celebrate their first away win of the season, a weight seemed to lift from the club.  

Before the weekend, for all his undoubted stature, Louis van Gaal had so far brought only boastful talk and unfulfilled expectations to Old Trafford.

But here at last, in their 12th Premier League game of the season, was hard evidence United could compete and win against the bigger teams.

Four days ago I wrote how Van Gaal desperately needed a win at Arsenal to justify the patience shown to him by United fans, and give them a reason to believe that better times might not be too far away.

While the performance against Arsenal was far from perfect and had some nervous moments, United showed resolve and discipline to grasp their victory.

Van Gaal took into account Arsenal's approach to the game, and the inexperienced and depleted nature of his own team, and devised a way to win, which involved allowing Arsenal to come on to them.

It represented an obvious and calculated risk, and United had to survive a torrid first 20 minutes, but they slowly began to look more comfortable in the second half and scored with two clinical counter-attacks.

The major concern with David Moyes last season was how alarmingly out of his depth he was whenever he came up against the very best teams.

So far Moyes has not won away in the Premier League at Manchester United, Liverpool, Chelsea or Arsenal in a staggering 47 attempts.

Louis van Gaal has now won at one of these clubs at his first attempt.

Beyond the win at the Emirates, the greatest source of optimism for United can perversely be found either sitting on their bench or recovering in a gym.  

Despite United’s injury-ravaged season, they could still boast a substitute bench at the Emirates worth around at least £100 million, which included Juan Mata, Ander Herrera and Adnan Januzaj.

And by the end of Saturday United’s injury list had swelled to include Luke Shaw, Falcao, Marcos Rojo, Phil Jones, Rafael, Daley Blind and Jonny Evans.

The obvious conclusion to draw is that if Van Gaal can secure a win at Arsenal and haul his side up in to the top four of the Premier League amid such problems, then imagine what he is capable of with a more settled and full-strength side.

An unseasonably mild night in north London could prove to be the turning point for Van Gaal's reign at Old Trafford.