By Cristiano Corvino
Around 100,000 supporters with cheeks painted in their club's black-and-blue colors gathered in Milan's seething Cathedral square, waving giant flags and setting off flares and fireworks.
"Forza Inter, Forza Mourinho, don't leave your number one," fans chanted in the central square, before Argentine striker Diego Milito scored twice to give Inter Milan an unprecedented treble.
One banner read "Mourinho, we will pay your return ticket."
Inter fans have grown impatient about the future of the Portuguese coach, amid continued media reports he may leave for Real Madrid almost immediately after the final.
"He is one of us. He has to stay," said a fan at Malpensa airport, before leaving for Madrid.
Fans also hailed Milito as their new hero. "It is fantastic, Milito is great," Inter fan Stefano told Reuters.
Many fans were too young to remember when their team won their second European crown in 1965.
"I wasn't born when we won the last cup," Inter fan Mario told Reuters.
Italian media reported that over 100,000 fans thronged the streets of Milan to start partying after the final whistle.
(Writing by Antonella Ciancio, editing by Justin Palmer)