The team responded well when rain forced the match to be cut short to 38 overs, which upset their momentum and favoured Australia, the fans said.
"We are a side playing very orthodox cricket with a natural flair. The overs restriction was something that was not in our game plan," said Hashan Tillekeratne, a member of the Sri Lankan team that won the World Cup in 1996.
Popular commentator Roshan Abeysinghe said the shortened innings suited Australia's attacking batsmen.
"We do not have the players to play the power game required in that type of scenario -- the 38 over slog was tailor made for them," the Sri Lankan said.
Australia completed a 53-run victory on the Duckworth-Lewis method in virtual darkness at the Kensington Oval in Barbados on Saturday, winning the World Cup for a record third successive time.
Adam Gilchrist's blitzkrieg was a key factor in the match, said coach and cricket writer Ranjan Paranavithana.
"He was unstoppable and was playing the same sort of destructive innings played by Clive Lloyd and Viv Richards in previous cup finals," he said.
Sri Lanka's bowlers contained Matthew Hayden and Ricky Ponting relatively well, but Gilchrist's superlative performance took them by surprise, Paranavithana said.
The island nation's fans believe the Sri Lankans faced a team simply too good for them on the day.
"I feel sorry for them. They did try their best and it is not a disgrace," said Sonali Perera, a bank employee.
She and her colleagues would greet the team on its return despite the loss, Perera said.
Elderly fan Stanley Weerasinghe said everyone knew the Australians were powerful and blamed bad luck.
"Sri Lankans just did not have the luck. They will be a powerful team at the next World Cup with only Jayasuriya, Muralitharan and Atapattu likely to retire by then," he said.
Sri Lanka's captain Mahela Jayawardena was unlucky with the toss and if it had not rained and Sri Lanka had batted first, then it would surely have been a different result, argued university student Dinum Pathirage.
Sri Lanka's president congratulated the national team's World Cup effort and pledged to help the side prepare for the future.
"I congratulate the captain and members of the Sri Lanka cricket team on the success in finishing as runners-up in the ICC World Cup 2007 tournament," Rajapakse said in a statement at the end of the two-month competition.
Sri Lanka's Buddhists, Hindus, Christian and Muslims alike had organised religious services to bless the national team and pray for their success.
Cricket, hugely popular in Sri Lanka, is one of the few things cutting across ethnic and religious differences on the troubled island.
Fans dressed in the Sri Lankan team's colours and waving the national flag braved rain to gather in their hundreds at playgrounds, clubs, hotels and bars showing live coverage of the match on giant screens.
But the party mood was punctured by Sri Lanka's Tamil Tiger rebels, who carried out air attacks on the capital, Colombo, during the match, forcing some people watching the game to flee for safety.
The rebels' campaign for a separate homeland in Sri Lanka has claimed more than 60,000 lives over the past 35 years.