Cape Town - Former Manchester United captain Wayne Rooney highlighted the change in attitude from the club's players and backroom staff after the Red Devils cruised to a 5-1 win over Cardiff.
In what was his first match in charge, caretaker boss Ole Gunnar Solskjaer steered United to a convincing victory as they scored five goals in Wales for the first time since Alex Ferguson was in charge.
It was a performance that was in stark contrast to Mourinho's last game at the helm - a 3-1 defeat to bitter rivals Liverpool.
And, Rooney feels the positive atmosphere at the club, coupled with Solskjaer's focus on attacking football, has facilitated the turnaround in form.
"Everyone from the staff to the kitmen, they weren't enjoying it," Rooney told BT Sport. "You can see the staff are happy today and the players are too.
"The lads played with a lot of energy, enjoyment and excitement.
"When you've got confidence, you put yourselves in positions to score goals. That's what we did. We were playing higher and the full-backs were higher. We pinned them back and created a lot of chances."
Next up for Solskjaer and the Red Devils is a home game against strugglers Huddersfield Town on Boxing Day.