The Spanish goalkeeper was in the Red Devils under-21 side that beat Liverpool on Monday and inspired his team-mate pre-game.
The Spanish goalkeeper has penned an 18-month contract with the Old Trafford outfit after returning to fitness and will provide first-team competition for compatriot David de Gea.
Coach of the under-21 team Warren Joyce has revealed that the former Barcelona stopper conducted a pre-match team talk before the clash against the Reds.
Valdes also played a motivational video of American athlete Dick Hoyt for the team to watch, showing him pushing his quadriplegic son in a wheelchair during marathons and other endurance events.
Joyce admitted that the dressing room was suitably impressed by Valdes’ actions.
"The lads are in the room listening to this; it was unbelievable,” the BBC quote Joyce as saying.
"I was going to do something but Victor said 'Guardiola used to do this'.
"He's a very humble guy and a model professional."
Valdes won three Champions League trophies and six La Liga titles during his time in the Catalan outfit’s first team and as such has a wealth of experience to call upon.
The goalkeeper tore his anterior cruciate ligament in March and has been recovering with United since leaving Barcelona in the summer.