MADRID: Real Madrid coach Rafa Benitez needs to improve his relatively poor record against Barcelona if he is to avoid the first genuine crisis of his tenure when he takes charge of his first La Liga 'Clasico' on Saturday.

Benitez, who cut his coaching teeth in Real's youth ranks after his budding playing career was ended by injury, promised entertaining, attacking football when he returned to take over from Carlo Ancelotti at the end of last season.

The much-travelled former Valencia, Liverpool, Inter Milan, Chelsea and Napoli manager has struggled, however, to shed a reputation as a defence-minded tactician and ominous rumblings of discontent have been building in recent weeks.

Real go into the clash at the Bernabeu three points behind leaders and champions Barca after they slipped to a 3-2 loss at Sevilla in their last outing. Defeat by their arch rivals on Saturday could spell the beginning of the end for the 55-year-old.

Real's deep-pocketed president Florentino Perez is not known for his patience -- Benitez is the 10th coach the construction magnate has appointed during his two six-year stints at the helm of the world's richest club by income.

Ancelotti led Real to their 10th European title and the King's Cup in his first season in charge in 2013-14 but was summarily dismissed after failing to win major silverware last term, when Barca won the treble.

Benitez -- who has won four, lost seven and drawn one of 12 matches against Barca over the past two decades with Real Valladolid, Extremadura, Valencia and Liverpool -- knows a bare trophy cabinet this season will not be tolerated but the early signs are not good.

As well as criticism of his tactics, reports in Spanish media have suggested his relationships with some of his key players, including FIFA Ballon d'Or holder and top scorer Cristiano Ronaldo and fan favourite James Rodriguez, are already starting to sour.

Add to that Ronaldo's recent poor run of form, at least by his high standards, and injuries to the likes of Karim Benzema, Gareth Bale, Sergio Ramos and Rodriguez, and it seems the football gods are lining up against Real and their coach.

To make matters worse, Benzema was put under formal judicial investigation this month in connection with an alleged attempt to blackmail his France team mate Mathieu Valbuena with the use of a sex video.

That kind of off-field distraction is the last thing Real need and it remains to be seen whether Benzema will be physically -- and mentally -- fit to face Barca.

Chasing a sixth La Liga title in eight years, Barca smell blood and their former forward Julio Salinas said victory at the Bernabeu would deal a big blow to Real.

Talisman Lionel Messi looks set to return from injury and fellow South American forwards Neymar and Luis Suarez have been in scintillating form in recent weeks.

"Barca is coming into the match as leaders, with a three-point advantage, and with Neymar playing out of his skin and Messi fit again," Salinas told reporters on Wednesday.

"What's more, Real Madrid have a lot of problems. If Barca win that could cause a great deal of damage."

Barca lead on 27 points after 11 matches, with Real on 24 in second and Atletico Madrid a point further back in third.