Rookie Leonardo, who announced on Friday he was leaving Milan after just one season in charge but 13 years at the club, was given a rousing reception by players and fans in the San Siro despite his team only finishing third this season.
"Leonardo, you will always stay in our hearts," read one fan banner while others criticised club president Silvio Berlusconi for not backing his coach publically and financially this term.
"For me it's not been work. I've had been here for too long to make extra observations about people," Leonardo told Sky after a rare Milan-Juve match which meant nothing on the field.
"It's been an extraordinary relationship. I don't know what I will do now."
Left back Luca Antonini, a regular under the Brazilian having previously been a fringe player, ran over and hugged his coach after netting Milan's first goal on 14 minutes.
Ronaldinho, not picked in Brazil's initial World Cup squad, had embraced his countryman with a tear in his eye before kickoff and rewarded the coach with the second and third goals.
Another limp performance by Juve, who will finish a lowly seventh, summed up Zaccheroni's interim spell in charge since Ciro Ferrara was sacked in January.
"It was a match in line with recent performances. We didn't play," the former Milan coach said. "When I came in as caretaker, it was a situation I accepted and I can't complain."
Neither side have announced a new coach for next season with several names being linked to Milan and Sampdoria boss Luigi Del Neri installed as bookmaker's favourite to move to Juve after reports Liverpool coach Rafael Benitez was not interested.
