Koeman insists they can happy, despite Gerard Pique's dismissal.
"When you win a game, get three points and score five goals, you can be happy," the Dutch coach said after the win.
When analysing the game against the Hungarian champions, though, Koeman gave an honest assessment of the victory.
"I think after the break we played 25 really good minutes," he added. "But what I liked less, and we have to improve and avoid, are those moments in the game when we switch off.
"If we are capable of playing the whole game at the same intensity and, above all, with that high rhythm with the ball, we are a really good team."