Court papers show the footballer was caught on a speed camera at 17:51 BST on 26 August Carrington Lane, near the entrance to United’s training ground and academy complex.
The police computer system recorded that someone logged in to see the evidence in the case after Garnacho had been twice written to about the speeding.
However the force said he did not respond to the letters to confirm he had been at the wheel of the car.
Once the prosecution began, Garnacho’s lawyers wrote to ask for the charge of failing to provide driver information to be withdrawn on the condition he entered a guilty plea to the original offence of exceeding the speed limit.
Garnacho was convicted and sentenced in a hearing conducted last week behind closed doors under the Single Justice Procedure.
