United and England captain Rooney has dominated the headlines since pictures emerged showing him, complete in Three Lions training kit, looking the worse for wear during the global break.
Rooney was criticised after being pictured drinking at a wedding between England games earlier in the month, but he said thoughts of the controversy could not have been further from his mind.
Rooney told a BT Sport reporter the furore had been a "big deal out of nothing".
Manchester United boosted their chances of reaching the Europa League knockout stages after thrashing Feyenoord 4-0 at Old Trafford.
Rooney's opener also means he is a goal shy of Bobby Charlton's all-time club scoring record of 249.
"It was a good win".
Manchester United, with the win, moved to second in Group A with nine points from five matches, one behind the leaders Fenerbahce, who beat Zorya 2-0, courtesy goals from Miroslav Stoch and Simon Kjaer. "He looks a top centre-forward at Atletico and I think we have to be in the market for someone like that".
The scorer then turned provider, teeing up Juan Mata to slide home the second on 69 minutes, and United eventually ran out 4-0 winners thanks to an own goal from Jones and a deft curled shot from Jesse Lingard.More news: Bernie Sanders Calls on Donald Trump to Rescind Stephen Bannon's Position
"I didn't know that [about the record]", said Mourinho.
"It is not the biggest competition obviously, but let's try, let's push".
"I know that it's hard".
He added that everyone showed that they wanted to "score more goals and get into a position where we are ahead", in the group as it comes down to the head to head record after all of the games are played. A bad performance with a good result is a happy moment but it's just a happy moment, not a happy future.
Another to impress in United's win was Henrikh Mkhitaryan, who produced a lively display and was substituted to a standing ovation after making only his second start under Mourinho.
The Portuguese manager has admitted the Armenia star is struggling to cope with the pressure at Old Trafford, but confirmed the former Borussia Dortmund player will feature against the Dutch side later this week. The Premier League is different.
"The best manager in Premier League history needed a few years to build a successful period, if the best needed time then others do too".