Alba: Clasico is a must-win clash for Barcelona

With Barca four points behind Madrid going into Sunday's meeting, full-back Alba knows that defeat could all but end their hopes of retaining their Liga crown.

Barcelona were the last side to beat Madrid in the league, but Carlo Ancelotti's men have won 15 and drawn three of their 18 fixtures since then, a run of form that has seen them charge to the top of the table.

"It's vital to win away to Madrid," Alba told Barca's official website. "We have to win in order to keep our title hopes alive.

"We're going to Madrid with the intention of winning the game. We know it will be difficult, but we want to play a good game and win.

"We will have to be very alert in defence because they are very dangerous on the counter."

Comparisons are frequently drawn between the two side's talismans, Lionel Messi and Cristiano Ronaldo, and Alba believes that the fixture will once again be a fine showcase for the pair.

"They are the two of the best players in the world," he continued.

"I've always said that I prefer Messi, but we have to be honest and recognise that Ronaldo is a beast and a very important player for Madrid."