Martusciello told juventus.com: “Sarri has always been present at Continassa (Juventus’ training base), he’s good.

“We have the final preparation in the afternoon and then we’ll see if he’s able to make tomorrow.”

The champions won both games against Napoli last season as they finished the campaign 11 points clear of their closest rivals.

The previous season, under Sarri, Napoli ran Juve much closer, the gap four points, and Martusciello is well aware Saturday’s game is no ordinary match.

He said: “Tomorrow evening’s match will be a special match and there will be many particular emotions, on a personal and professional level.

“Our objective is to win, therefore it is crucial that everyone is on the same page.”

“Tomorrow is an important match for us, for them and for the world of football.”

Juventus, though, will be without captain Giorgio Chiellini, who is to undergo surgery in the coming days after suffering cruciate ligament damage during training on Friday.

The club said the defender suffered “a sprain of the right knee and lesion of the anterior cruciate ligament”.

Summer signing Matthijs de Ligt is likely to come in for his debut.

Aaron Ramsey is expected to have to wait until after the international break to make his first appearance as he continues to build up his fitness following his summer move from Arsenal.

Napoli boss Carlo Ancelotti believes the Juventus match will show how well equipped his side are to mount a title challenge this season.

He told the club website: “It will give us a good idea of where we stand.

“We’re playing the title favourites and we know how good Juventus are, but we feel confident.”

In their opening game of the season Ancelotti’s side let a two-goal lead slip against Fiorentina but managed to hold on for a thrilling 4-3 win.

He said he wanted to see an improvement on last week’s performance, adding: “I want a competitive team that sets out to play their own brand of football.

“We have to be on the ball both going forward and defensively – and in that sense I expect to see an improvement on last week’s game in Florence.

“The result won’t be decisive, but it’s very important because this is a huge match.

“We’ll play it with character and the desire to express our potential.”