Casillas slams Champions League balls

"I am sorry but it has got to the stage where it just can't be allowed to continue," Casillas, who is also Spain's number one keeper, said in an interview published in Spanish sports daily As on Tuesday.

"How they make the balls makes things difficult these days, particularly the one for the Champions League," he added.

"The flight is terrible, you saw that at the Confederations Cup and the European Championship."

The balls for the Champions League, the Confederations Cup and the European Championship are manufactured by German sporting goods maker Adidas.

"The ball used in the league is a bit better, it can do strange things but not many," added Casillas. "The other one is a complete disaster."