Juve hold an eight-point lead over second-placed Roma at the summit of the Italian top flight, with Napoli four points further back after 20 games.
Benitez's men have not suffered in defeat in their last seven league outings, a streak which looks likely to be extended when struggling Chievo visit Stadio San Paolo on Saturday.
And defender Maggio believes that Napoli can end their 24-year wait for a third Scudetto.
"A 12-point deficit to the leaders is a lot but you can never say never in football," Maggio told Radio Kiss Kiss.
"Of course Juve look unstoppable at the moment and Roma look to be the team we have a chance of catching, but we can't ever give up."
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