In the end, it was probably our best performance of the season (although admittedly that's not saying much) - but one that also simultaneously showed how far we are behind the Premier League pacesetters.
United may not, as Mourinho complained, have any "mad dogs" in their side, but there was at least some bite about this display after recent tame efforts against Crystal Palace here, and at Southampton. The spirit, fight, endeavour and effort cannot be faulted but there was simply a lack of quality.
That was appreciated by United's fans as a starting base, but there was little to suggest this was a team whose season was about to burst belatedly into life. And while this was a performance that contained many admirable qualities when measured in grit and character, it showed no signs of being the early stage of development into a team that could claim the big prizes.
United's attack was more fluid and mobile with Martial and Marcus Rashford selected ahead of Lukaku but there was still a lack of creativity, and while the effort was there, the real spark was missing.
Mourinho will be pleased at the manner in which United responded to Arsenal's goals, helped by the Gunners' sloppiness, and these were players who were undoubtedly putting in the work for their manager. This is a stodgy United side producing stodgy performances - a pale shadow of a side that will chase the big prizes.
Arsenal remain a team in transition under Emery but do, at least, appear to be headed on an upward trajectory.
What was not in doubt was the commitment of United's players. They were, despite all the noises surrounding Mourinho playing for their manager.
No-one can doubt the honesty and character. Those who forged a draw against a team unbeaten in 20 matches gave their all.
The problem in the wider context is this United squad is nowhere near good enough when measured against the best.
The fact this was regarded as a reasonable improvement on recent offerings, despite another draw, is a commentary on United's season so far.
At no point did you ever feel that the Reds would go on and win. Even with a thrilling tie finely poised on a knife-edge, Arsenal created the better chances with United indebted to David de Gea despite his untimely error in the first half that led to Shkodran Mustafi's opener. The visitors - without a win at Old Trafford in the league for 12 years - looked more likely to win it.
Mourinho shuffled his pack again with something of a "shop window" XI, his hand slightly forced by a raft of injuries with Chris Smalling, Phil Jones and Luke Shaw all sidelined along with the suspended Ashley Young, Diogo Dalot impressed as one of seven changes and several of Mourinho's fringe players may have forced him to reconsider. Eric Bailly has not been seen since the Newcastle tie but was commanding and strong. Nemanja Matic inexplicably got the official Man of the Match award, but I'm giving it to the Ivorian. To his credit, this was a marginally improved performance from Matic but still nowhere near his best.
Marcos Rojo is the biggest s***house in the game but did well alongside Bailly in a 3-4-3. Matteo Darmian, in an unfamiliar role at left wing-back was also impressive even though he looks likely to leave in January.
A much improved performance and one that left us feeling positive despite a fourth game without a win.