Cristiano Ronaldo says it is now "kill or be killed" in the Champions League as the remaining 16 elite teams enter the knock-out stages.

"From now on, all games are important," Ronaldo told uefa.com ahead of Manchester United's first leg against Internazionale in Milan. "It's time to kill or be killed. Whoever loses will exit the competition and we don't want to lose, we don't want to get stuck along the way. It will be a difficult game, but I think that Manchester United have a better team, and we'll do our best to win it."

Inter have won the Scudetto for the past three seasons and are on course to do so again, but Ronaldo thinks United have the edge after winning the European club competition last season.

"They're a team we need to respect," the Portugal winger said. "They're a team with very experienced players, but we also have our aces and great players. We have a more experienced team, we're the reigning champions. It will be a good game, a well-contested game."

Ronaldo says he wants to repeat the sensations he felt when United beat Chelsea in last season's final in Moscow, even though he missed a penalty in the shoot-out.

"I always had a great ambition to win the Champions League, because it isn't obtainable for every player. It was my first Champions League win, so the emotion was spectacular. I remember Edwin van der Sar saving Nicolas Anelka's penalty and, for me, it was like the earth stood still. It was a really brilliant sensation."