Mourinho dropped high-profile duo Paul Pogba and Romelu Lukaku after recent disappointing performances which have brought only three points from the past 12 available – and, while quality was lacking, no-one could doubt his side’s endeavour and character.
Goalkeeper David de Gea made an uncharacteristic error as he failed to deal with Shkodran Mustafi’s tame 26th-minute header, which Ander Herrera could not clear before it crossed the line.
United were swiftly level through Anthony Martial after Arsenal keeper Bernd Leno could only half-clear a free-kick to set up an exciting second half.
Substitute Alexandre Lacazette scrambled Arsenal back in front after 68 minutes but United were on terms once more within seconds as Jesse Lingard pounced on Sead Kolasinac’s attempted backpass.
De Gea redeemed himself with a succession of fine saves as both sides had to content themselves with a point, with United now eighth in the Premier League and Arsenal, who extended their unbeaten run this season to 20 games, dropping to fifth.
“As always we made mistakes and we paid for the mistakes,” said Mourinho.
“Today was more the same, but with great spirit and people ready to have a go and fight hard. It was a credit to the team.”
Mourinho’s men show grit, but little quality
Arsenal will, ultimately, probably be happy with a point at a ground where their recent record is miserable, and against opponents who were attempting to put down a marker after recent criticism.
Gunners boss Unai Emery, however, will feel disappointment that they did not leave with all three points after twice holding the advantage only to concede it quickly.
Emery’s frustration was obvious when Lingard scored United’s second equaliser moments after Lacazette had restored their lead, as he knew had they held their advantage a little longer there is every chance United could have become frustrated.
The manner in which it was conceded will have also infuriated the animated Emery, United striking back right from the kick-off with the aid of Kolasinac’s error.
On the plus side, Arsenal coped well with United’s predictable late aerial siege and this is a point that consolidated their good start to the season and extends that fine unbeaten sequence.
Emery may have wanted the win as Arsenal failed to reproduce the electrifying form that beat Spurs in the north London derby but there was still plenty to satisfy him.
Man of the match – Eric Bailly (Manchester United)
Manchester United manager Jose Mourinho: “We scored four goals and drew 2-2! As always we made mistakes and we paid for the mistakes.
“Today was more the same, but with great spirit and people ready to have a go and fight hard, it was a credit to the team.
“They went to the limit and were really tired. Some of them had not played all season, Chris Smalling playing in very difficult condition, but Arsenal were only dangerous when we lost the ball in bad areas.
“Even from our bench you could feel the little panic when the ball comes to our defensive third.
“The spirit was Manchester United level but we miss certain qualities.
“I have to disagree with people who try to compare this to teams of Roy Keane, Ruud van Nistelrooy, Nemanja Vidic. Give us a break and time. I am happy with the soul and heart, but we are not consistent and uniform.”
Arsenal manager Unai Emery: “I think we controlled the game, the second half better than the first. We could have won this match in certain moments, but they equalised very quickly after both our goals.
“We need to improve defensively, but we need to have balance and not lose our attacking chances.
“We perhaps lost a bit of control there but we created lots of chances after 2-2 and I am very proud of our performance. We wanted to win but we can feel this point is good.”
United continue leaking goals – the stats
Manchester United manager Jose Mourinho has only lost one of his 16 games against Arsenal in the Premier League (winning seven and drawing eight) and remains unbeaten in home games in the competition against them.
Arsenal are now unbeaten in their last 20 games in all competitions, their longest such run since November 2007 (28 games).