Ganguly said: "Hats off to them. They played like great champions.
"Australia were a better team than us but we can go back home with our heads held high."
Australia, unbeaten throughout the tournament, became the first side to win the trophy three times as they cruised home with 10.4 overs to spare at The Wanderers.
They scored 359 for two from their 50 overs, the best score ever recorded in a World Cup final, before dismissing India for 234.
Ganguly said India's pace attack, after a fine tournament, had failed to fire. "It was one of those bad days for them. I think they bowled too short."
Sachin Tendulkar, named man of the tournament, was India's only real hope of a miracle fightback but he fell for just four in Glenn McGrath's opening over.
Tendulkar, presented with his award by West Indian great Gary Sobers, said: "It didn't happen. The bowlers found it tough to put the ball in the right areas. It was just one of those days."
