The Portuguese coach claimed during the week that Juventus would not be entitled to view winning this season's Europa League as 'success', given the Serie A titleholders started the season in the Champions League.
However, Benitez, who has had a strained relationship with Mourinho ever since his time in charge of Liverpool, has now decided to stand up for the Bianconeri, whom Napoli face at the San Paolo on Sunday night.
"He talks too much," the Spaniard told reporters on Saturday. "Whereas I like to let facts do the talking.
"At Liverpool I knocked his Chelsea out of the Champions League when we had half the money ..."
Turning his attention to Juventus but without moving off the issue of financial muscle, Benitez argued that third-placed Napoli will have to continue to splash the cash if they are to reach the Old Lady's level.
"But their squad is stronger and this aspect makes the difference. If then you have injuries and various problems it becomes difficult.
"We have dropped around eight points that could have made the difference. A winning mentality can also make the difference and we're always thinking about things that we need [in the transfer market].
"But it's not the same to take a player to London or Madrid, as it is to Naples. We know this. But we must aim to sign players of a level with which we can meet the Financial Fair Play (FFP) rules.
"But the difference between the turnovers enables one team to create a winning structure and squad every year.
"With a €300 million turnover, Juve can buy the strongest players every year. They have been doing it for a lifetime.
"You must spend every year in order to compete. You can only acquire a winning mentality by signing players used to winning.
"We should not be a club that aims to win a cup every 25 years. There have been mistakes but we have grown."
Despite the fact that he feels the financial playing field is tipped in Juve's favour, he fully expects his Napoli side that they can compete with the two-time defending champions.
"Our intention is to go into a game of this kind with the right attitude," the former Valencia boss explained.
"Our squad is strong but [second-placed] Roma and the Bianconeri are doing better.
"We must learn to manage games and maintain the level we showed in the Champions League and in some Serie A matches, like against the Giallorossi and the two Milan clubs [AC and Inter].
"I cannot say too much about how to beat Juventus; Conte is listening! We have to try to do well against a team that is having a spectacular season.
"Our best players will have to make the difference in a game like this."