But the former Barcelona captain insists he's not among the knockers.
“Many people in the game can’t stand Mourinho - [but] I am the opposite.
“Mourinho may not create the most beautiful style of football. But he does create winners. Nobody turns his players into winners more than he does.
“This man gets the maximum out of his teams.”
On Demba Ba's winner for Chelsea against Champions League opponents PSG, Koeman declared: “Was it a piece of magic ? No. Was it the result of a brilliant attack? No. It was the result of a bunch of players with a winning mentality thanks to their coach.
“He comes out with strong stuff. He did it before the PSG match in London. But he achieves what he promises.
"My God, I can only show huge respect then.”
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball