Barcelona forward Ronaldinho has admitted he was keen to prove wrong critics who said he was overweight, after his side's 3-0 win over Athletic Bilbao on Sunday.

Photos of the 26-year-old showing a roll of fat around his waistband after he had taken off his shirt at the end of Wednesday's 2-1 Champions League defeat to Liverpool, have sparked a heated debate about the Brazilian's weight and form.

Newspapers in both Madrid and Barcelona made comparisons about Ronaldinho's apparent loss of fitness by publishing photos of the forward taken in 2003 and 2004 in which he appeared to be leaner and more muscular.

But having put on a scintillating display in the Nou Camp on Sunday, the Brazilian stripped to the waist at the end of the match and jokingly challenged pitchside photographers to snap him.

"I don't have anything to hide. I always change shirts with the other players," Ronaldinho told reporters.

"Over the last week photos have come out insinuating I'm fat but I feel fine. I have always looked after myself and am in better shape then ever. With everything that has been said recently I was motivated to play even better."

In the first half against Bilbao, Ronaldinho was involved in the build up for the second goal, scored by Xavi, and set up returning Cameroon striker Samuel Eto'o for the third.

After the break, only the woodwork prevented Ronaldinho from adding to his 16 league goals this season.

The photos of a shirtless Ronaldinho on the front of Monday's newspapers were more flattering.