Barcelona star Lionel Messi admits he didn't enjoy the last fortnight of the season.

Defeats to Liverpool and Valencia ended Barcelona's hopes of a historic treble, but Messi has the chance to lift silverware this summer with Argentina at the Copa America.

"I finished the season more tired and frustrated mentally than physically after what happened in the last 15 days, especially the Champions League exit," he said.

"Physically I had to rest, I played less than I did in other years."

Messi threatened to quit international football after Argentina's disappointing World Cup display in Russia last summer but, after a few months away, he has come back for more.

"I feel great," he said. "We have a group that has the hunger to do good things."