coach Carlo Ancelotti said an intense month of pre-season training and friendlies had left his players "tired" in their 4-0 defeat to Barcelona, but he insisted his squad is ready for the new Serie A season.
Second-half goals from Antoine Griezmann and Ousmane Dembele, along with a brace from Luis Suarez after the break, earned Barcelona a convincing win in Michigan, though Ancelotti claimed the opening two strikes should not have stood.
Suarez buried the rebound after a Griezmann shot was saved in the 48th minute, and the Frenchman scored himself eight minutes later after a pass from Jordi Alba, who appeared to be in an offside position.
Ancelotti defended his side's performance, telling reporters: "We played well in the first half but then we were affected by those two offside goals at the start of the second half.
"We were up against a magnificent team and afterwards they took control, but those two goals shouldn't have been given and they changed the match.
"I think we were also a little tired due to the heavy training loads after a month of intense work. I don't see any problems other than that."
Napoli travels to Fiorentina for its Serie A season opener on August 24 having won three, lost three, and drawn one of its pre-season friendlies.
Despite the team's mixed form and relatively modest activity in the transfer market, with three of its six major signings being goalkeepers, Ancelotti remains optimistic about Napoli's chances of improving on their second-placed finish in 2018-19.
"My general impression is good after these two matches with Barcelona," he said, reflecting on Saturday's defeat and the 2-1 reverse in its previous outing against the Blaugrana.
"We'll build on this as we continue to work towards the start of the season.
"I'm happy with the work we've done both on our training camp and in these international friendlies we've played. We have a top-quality squad and I'm sure we can have an excellent season.
"I've seen a lot of things I like from the lads and the overall feeling is positive. We'll be ready when the season begins on 24 August."