The Brazil international, one of the best defensive midfielders on the planet, has sparkled at Old Trafford after being eased into life in the Premier League, following his summer move from Real Madrid.
Ahead of the Europa League group decider with Real Sociedad, Casemiro sat beside the boss at a press conference and enthused about the Dutchman's insatiable winning appetite.
"I believe that, after being in football for quite a while, despite the fact I am only 30, his obsession for winning is what surprised me the most," said Casemiro.
"I think he's got many strengths.