The Portuguese named a strong line-up in Rotterdam but they were unable to prevent a second defeat in five days, brought about by Tonny Vilhena’s 79th minute winner, following the earlier loss to Manchester City at the weekend.
But Mourinho insists he will not react any more acutely to the recent losses than he did when United made a 100 per cent start to the new campaign before the international break.
“When we won the Community Shield and the three league matches I was not on the moon, saying we are a phenomenal team who will destroy the opponent,” he said.
“I just said ‘good result, good result’. I know it is not a case of clicking your fingers. I think both of these results is a punishment for the team because we did not deserve it.
“I think the game on Sunday [against Watford] will be an independent game, a new event, another match, it starts at minute zero at 0-0 so it has nothing to do with the previous two matches.
“Obviously when you lose matches the mood, the feeling, is not the same. We are experienced people, the players are good guys. I know they want to work.”
United travel to Vicarage Road on Sunday in need of a result to belay the fear that their albeit fledgling season is unravelling.
Mourinho spoke previously of the disruption the Europa League can have on scheduling but neglected to expend upon his grievances at full-time in the Netherlands.
“There are no miracles in terms of the players’ soul,” he added. “You win matches and people are happy and full of confidence. You lose matches and people are sad and they feel it.
“That is the normal feature of football players. I am here to not let them be in a negative mood or negative period because we lost two matches. I think [they were] two matches where we could have played better but two matches where we did not deserve this. I know we play at midday on Sunday and it is now 9pm on Thursday. But let’s not make an excuse for Sunday