The reigning Spanish champions were held to a goalless draw by Real Betis last weekend, their second such result in a week, losing ground in the title race.
Although Los Blancos remain in second position in the La Liga table, two points off leaders Atletico Madrid, their arch-rivals Barcelona have a game in hand. A win for Barca in Thursday's game against Granada would propel them to the summit.
With just five games remaining in the season, Zinedine Zidane's side cannot afford any more slip-ups. This is especially true as they have a more challenging home-stretch of the campaign compared to their top-three rivals.
Meanwhile, the Rojillos have little to fight for as they remain 10 points clear of the bottom-three and are all but assured of retaining their top-flight status.
However, the Pamplona outfit have caused problems for Real Madrid in the past and the holders cannot afford to underestimate their threat.
Real Madrid vs Osasuna Head-To-Head
In 35 previous clashes between the sides, Real Madrid have beaten Osasuna on 23 occasions, while losing only five times.
However, their match in Pamplona earlier this season ended in a goalless stalemate.
Real Madrid Form Guide (all competitions): D-D-W-D-D
Osasuna Form Guide (all competitions): D-W-W-W-L
Real Madrid vs Osasuna Team News
The embattled holders were dealt another major blow after Daniel Carvajal was ruled out for the rest of the season with a hamstring injury.
That leaves Zidane in a spot of bother, with Ferland Mendy also doubtful for the clash. Nacho will need to be at left-back while Eder Militao is the likely option to fill in for Carvajal at right-back.
Lucas Vazquez and Federico Valverde have long-term injuries.
Injured: Daniel Carvajal, Lucas Vazquez, Federico Valverde, and Ferland Mendy
Goalkeeper Ruben Martinez is recovering from a hand fracture. Los Rojillos will stick with Sergio Herrera in goal, while Inigo Perez is out with a muscle injury.
Head coach Jagoba Arrasate might tinker with his formation a little after the loss to Celta Vigo, with Javi Martinez and Roberto Torres in line to start. Meanwhile, Chimy Avila is also in with a shout for a starting berth ahead of the erratic Ante Budimir.
Injured: Ruben Martinez and Sergio Herrera
Real Madrid vs Osasuna Predicted XI
Real Madrid (4-3-3): Thibaut Courtois; Eder Militao, Raphael Varane, Sergio Ramos, Nacho; Luka Modric, Casemiro, Toni Kroos; Vinicius Junior, Karim Benzema, Marco Asensio.
Osasuna (4-5-1): Sergio Herrera; Facundo Roncaglia, Jonas Ramalho, Unai Garcia, Juan Cruz; Kike Barja, Darko Brasanac, Jon Moncayola, Roberto Torres, Ruben Garcia, Chimy Avila.
Real Madrid vs Osasuna Prediction
It's no secret that Los Blancos have lost steam lately, but with a title defense on the line, expect them to turn up the heat in this game.
Prediction: Real Madrid 2-0 Osasuna