Van Gaal fell to the ground in front of Dean to make a point about Alexis Sanchez’s theatrics during the second half at Old Trafford.
It was a funny episode on what was a superb afternoon for Man United, with Marcus Rashford scoring twice and creating another against the Gunners.
“I’m always sitting on my bench but my emotion today was a bit too high,” van Gaal said.
“I apologised to the referee. I have to control my emotions.”
In the space of 90 minutes, van Gaal and United managed to completely dismiss the negativity that has surrounded the club over the course of the campaign.
As well as Rashford, Timothy Fosu-Mensah made his Premier League debut for United and it was excellent to see the side control the match against Arsenal with such a youthful XI. The hope is that the result acts as a catalyst for a strong end to the campaign.