Speaking to Sky Sports , he said: "Ronald Koeman pushed me very hard last season and I liked that. People can have opinions on the outside about Koeman and how things worked out with me but he did push and I enjoyed that.
"I probably worked harder myself when he was at Everton to keep improving, to improve everything, fitness, diet, defensive work, trying to get more goals, I was focused on everything.
"He had a belief that I could be much better than what I was showing. Obviously it didn't work out for him at Everton but he is a top coach."