Mertens admits Sarri transformed his game when they worked together in Naples.
He said, “In the first season with Sarri I only played six games as a starter. So I was always mad, [but he would say:] 'You are so important for me, for the team, and don't worry, you'll have your chances.' One day he put me as a striker and I'm very happy [he did] because it changed my life. He just put me there and said: 'I'm sure you're going to do it well.'
“It's incredible because I never came here to be the all-time top scorer of this club."