Cristiano Ronaldo is "a beast" but Real Madrid should fear four-time FIFA Ballon d'Or winner Lionel Messi, Barcelona full-back Jordi Alba warned on Wednesday ahead of Sunday's crucial El Clasico showdown. "I think they are two of the best players in the world but out of the two of them I'll go with Leo," Alba said when asked which of the two players should be feared more during Sunday's game at the Santiago Bernabeu. "I don't just say that now because I am in the same team, I thought that when I was at Valencia." "I think Cristiano, you have to be honest, he's a beast, he's a very important player for Real Madrid. When Madrid are not at their best he always pulls through," the 24-year-old said. "But we have Leo and other players and I think we are more of a team than a bunch of individuals." Ronaldo, the FIFA Ballon d'Or holder, has scored 41 times in 37 appearances for Madrid this season, including a double in Tuesday's 3-1 win against Schalke 04 which secured Real Madrid's place in the UEFA Champions League quarter-finals. Messi overtook Paulino Alcantara to become Barcelona's all-time leading scorer by netting a hat-trick during the Catalan giants' 7-0 rout of Osasuna in the Spanish La Liga on Sunday. The three goals brought Messi's career tally for Barcelona to 371 in all games, breaking the club record of 369 held by Alcantara since 1927. Leaders Real host Barcelona on Sunday night, when a win would stretch their lead over the defending champions to seven points and deal a severe blow to Barcelona's chances of a fifth title in six years. Barça are third with 66 points, a point behind second-placed Atletico Madrid. "Madrid are a really good team. This year they are playing at a great level. It is going to be a very difficult match, very complicated, at their ground," added Alba. Source: FIFA.com