The 18-year-old, introduced after 55 minutes, helped Mourinho’s side to a 3-1 victory over Northampton Town with a goal and an assist on his League Cup debut.
His goal on 75 minutes – launching the ball into an empty net after rounding keeper Adam Smith – was indicative of an energetic, determined performance.
Reflecting on Rashford’s opportune goal, Mourinho claimed some players in this Man United squad struggle to mirror the youngster’s ebullient attitude.
“I think that situation is not just about the speed; it’s more about the attitude,” he said.
“I don’t think you need to be very fast in that situation, but you need to be mentally aggressive – to put pressure on the defender.
“This is what he has, and it’s something over people don’t have. So, no lost ball, he puts very good pressure on the keeper and he gets an easy goal.”
It was, above anything, a glorious symbol of exactly why Rashford is so adored by United fans: that raw, unshakeable energy and attacking fervour, fixated purely on terrorising opponents, is the type of thing any supporter would salivate over.
Mourinho’s recent comments have recently garnered a swathe unwelcome criticism, but one cannot argue with the fact that some players in this squad don’t espouse the same buoyancy, the same effervescence in their approach as Rashford.
There is, amongst most players, an element of caution, a nagging conservatism in their style. This has been fostered, no doubt, by various set-backs and reality checks throughout their careers.
But Rashford – hitherto untouched by such afflictions – is refreshingly unique, playing instead with complete fearlessness.