The Spanish midfielder claims that he has improved as a player under the tutelage of the Portuguese manager this season.
"Mourinho is a winner, he's very competitive," said Herrera via The Express. "He demands 100 per cent from his players. He gives you all the confidence in the world from the first day. I've improved as a player with him and I'm very grateful for that.
"I hope there will be better times in the future, too, but it's the best time of my career. I'm more consistent, I feel an important member in the team. I know the coach considers me an important player. I'm enjoying myself and I feel loved."