Arsene Wenger's men were dreadful going forward at Old Trafford and, were it not for some resolute defending, they might have left with nothing at all.
Juan Mata's goal in the 68th minute looked to have secured a win for United, but up stepped substitute Olivier Giroud to head home from Alex Oxlade-Chamberlain's cross with minutes remaining.
Jose Mourinho summed up the stalemate perfectly in a post-match interview, telling Sky Sports: "Of course it is two points dropped. We were the best team by far.
"They had no chances to win. They are the lucky ones and we are the unlucky ones."
An Arsenal equaliser looked incredibly unlikely as time wore on, with Rio Ferdinand paying the ultimate price for celebrating too early.
In the below video, taken on Ferdinand's Snapchat, the former centre-back ridiculed Arsenal fans when Mata put United ahead and was quickly made to regret it.
He said: "I don't want to hear it. I don't hear what you've got to say. What are you saying now? Manchester United one, Arsenal nil!
"Take that, go to sleep, sit back down Arsenal fans. I don't want to hear it. Goodnight."
And then it happened. In the 89th minute, Giroud struck to secure an undeserved point and spoil the party at the Theatre of Dreams.
Cue another video from Ferdinand who, with his head in his hands, huffed and puffed about the fact his beloved former employers had just squandered their lead.
That's what you get for being cocky.
Arsenal were unquestionably fortunate, but for Arsene Wenger, his men showed grit in what was a difficult fixture.
He said, per BBC Sport: "We didn't create many chances. In the second half United were on top of us and deservedly led 1-0.
"But we came fighting back to 1-1. We showed steel. We want steel and style but we showed more steel today. We have very good squad spirit."