Benitez developed his reputation as one of the world's best managers while in charge of Valencia at the turn of the century.
The Spaniard would go on to manage Liverpool, where would he win the Champions League and FA Cup, for six years before arriving at Inter in 2010.
And despite winning the Italian Super Cup and Club World Cup, he was fired in December 2010 with the club sitting well off the pace domestically, as well as falling out with the board over their transfer plans.
And Carboni, who played under Benitez at the Mestalla, believes his former manager was treated harshly by the Italian giants.
"Rafa Benitez is a great soccer coach, a teacher of perfection and a good strategist," the former Italy international told Tribalfootball.com.
"His career speaks for itself. Inter was not a good situation because he found a team that was already overwhelmed with titles & trophies, parties and, on top of that, that pre-season there had been his star players resting after the World Cup.
"I remember that he started the season with only 11 players and many youngsters. So, he didn't manage to communicate to the squad his ideas of football, which are totally different to Mourinho's tactics.
"But he managed to win 1 Italian Supercoppa and the Club World Cup; a title that had been missing from Inter Milan's trophy cabinet."
Carboni became sporting director of Valencia in 2007 after retiring from his playing career.
And the 55-year-old revealed Benitez, now in charge of Dalian Yifang, tried to poach players from his old club when he was in charge of Liverpool.