"I think in the past few months we have had a few lapses here and there. Nobody will give us a chance, to be really honest, but we are happy to enter the tournament as underdogs," Mathews told reporters.
"We are confident, we have prepared extremely well - in Sri Lanka and England for the past few days, it's been really good. Hopefully we can play tomorrow's practice game (against Australia), and get a good practice out of it," he said.
"Everyone has got a chance, no one can write anyone off and I'm sure it will be a very exciting tournament.”
Mathews, 29, welcomes maverick paceman Lasith Malinga back to the squad after completing his rehabilitation from a knee injury.
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The 33-year-old, who quit test cricket in 2011, played the last of his 191 one-day internationals in 2015 and returned to international cricket with Twenty20 matches in Australia earlier this year.
"We look forward to utilising him in the matches," Mathews added. "He's very keen to get on the park. He hasn’t played 50-over games in the recent past but he has played a lot of games in the IPL which is very intense."
Sri Lanka play South Africa in their first game of the campaign on June 3 before facing their sub-continental rivals in the next two matches.
(Reporting by Hardik Vyas in Bengaluru; editing by Mark Heinrich)
