Mertens: 'We need to spend more to win the Scudetto'
Napoli have been linked with a move for Mauro Icardi and have already signed Kostas Manolas and Eljif Elmas. They have sold Amadou Diawara to Roma in a swap for the Greek. They also signed Giovanni di Lorenzo from Empoli, who sustained relegation last season.
In an interview that Mertens gave to ESPN, he talked about a possible Scudetto challenge by Napoli.
He said: "Six years ago I came here with Callejon, Higuain and Albiol, lots of transfers and lots of quality footballers. The problem is that we are always close to taking another step, and it would be important to do it now.
"We must continue to do well, perhaps by purchasing other players . When you buy the best players you have a better team. But many of us have been playing together for years, but in the end it takes more to win something."
Napoli start their Serie A campaign away to Fiorentina in what could be a tricky game.