The retired midfielder has hailed his former team-mate's ability after the goalkeeper was dropped in favour of Antonio Adan
Guti says Iker Casillas "knows he is the best in the world" and backed him to win his place back in the Real Madrid side.
Jose Mourinho opted to start Antonio Adan for the 3-2 defeat to Malaga, with the club captain forced to settle for a place on the bench.
The Portuguese has since defended his decision and insisted the move was purely down to footballing reasons and not because of a problem between the pair, with Guti offering his backing to his former team-mate.
"It's not about choosing between Iker or Mou, the most important thing here is Real Madrid. It's fundamental that the team return to normal as soon as possible," he told AS.com.
"Iker knows that he is the best goalkeeper in the world and that everything will return to normal soon."
The defeat leaves Blancos in third place and 16 points adrift of league leaders Barcelona.