The Mexican always delivers when coming off the bench - as he did again in the recent Aston Villa game - and is clearly performing with renewed vigour and energy, scoring at Newcastle on Saturday. Moyes has noted the Bayern defenders struggle in defence against genuine pace and will have been encouraged by the way Danny Welbeck troubled the visitors.
Chicharito is a natural born scorer and has the air of a lucky charm about him. It is impossible not to draw comparisons with Ole Gunnar Solskjaer, who was also a cheerful presence with an assassin's touch when presented with a sight of goal. Like Hernandez, the Norwegian had to bide his time and maximise his opportunities on the pitch.
In 1999, in the most incredible climax to a major final, Solskjaer wrote his name into folklore with one prod of his boot and earned legendary status at Old Trafford that will last forever. The setting may be different in a week's time when the Allianz Arena stages the second leg with the quarter-final tie delicately balanced at 1-1 but it is another of Europe's grandest stadia.
Memories of Camp Nou have been understandably stirred by this latest meeting of the two gigantic clubs. 'Who put the ball in the Germans' net?' asked the Stretford End on more than one occasion on Tuesday night. 'Ole Gunnar Solskjaer'.
It is not difficult to imagine Hernandez being thrown on in a bid to send United through during a dramatic conclusion in Bavaria. Perhaps the Reds will be level or even trailing 2-1 when he will inevitably be asked to supply a decisive moment when it matters most.
With Dante an obvious Bayern replacement for the suspended Javi Martinez, the Brazilian struggles to contain speed and the acceleration of Hernandez, when up against tiring legs, could hold the key to a famous and most unexpected triumph to take United into the last four.