Barcelona great Xavi praised the "spectacular" Cristiano Ronaldo, but said the Real Madrid star's problem was how good Lionel Messi is.

Ronaldo and Barca maestro Messi are regularly compared and always in the discussion over the greatest players of all-time.

Xavi, a former team-mate of Messi's at Camp Nou, said Ronaldo deserved credit, but feels the Portuguese attacker is behind the Argentinian.

"Cristiano Ronaldo is a born scorer, a spectacular footballer," he told A Bola TV.

"The problem is that there is Messi, who for me is the best player in history.

"That is the only problem that Cristiano Ronaldo has, but he is a player who scores and continues to mark an era."

Ronaldo's Madrid are in Champions League action on Tuesday, hosting rivals Atletico in the first leg of their semi-final.

Meanwhile, the battle between Barca and Madrid for LaLiga glory is set to go down to the wire, with the former on top but having played a game more.