"I have played with almost all of them (the Argentineans) in the national team," Cambiasso told Inter.it on Monday.

"Riquelme is their playmaker. If you let him play he can be very dangerous. At club level I have played with Forlan who shouldn't be underestimated because he has been top scorer in Spain."

Riquelme and Forlan combined to score half of Villarreal's six goals in the tournament so far.

Favorites Inter play Villarreal at home in their first-leg of the quarter-finals and Cambiasso stresses that it will be a big mistake to underestimate the 'Yellow Submarines'.

"We know it will be a lot more difficult than it seems because certain teams without a big name are often underestimated," he said.

"There are other more famous teams with a long history. Instead, Villarreal are creating their history now."