Alvaro Arbeloa has urged Real Madrid to show "strength in adversity" after they lost control of the LaLiga title race.
Los Blancos fell to a late 2-1 defeat at Osasuna, meaning Barcelona could reclaim top spot when they face Levante on Sunday.
The loss at El Sadar also means that only one of the last six Madrid managers have won away to Osasuna on their first league visit (Zinedine Zidane in 2017).
It was also Arbeloa's first defeat in LaLiga since taking over from Xabi Alonso, ending a five-match winning run in the competition.
Despite the result, the Spaniard has called on his side to show character ahead of their Champions League play-off second leg against Benfica on Wednesday.
"I hope it's [the loss] nothing serious, because we're fighting for our lives again in four days. A team shows its strength in adversity," said Arbeloa.
1 - Álvaro Arbeloa will manage his first LaLiga match against Osasuna; only one of the last five Real Madrid managers has won on his first league visit to El Sadar: Zinedine Zidane in 2017 (1-3). Challenge. pic.twitter.com/Pum5hz6U1P
— OptaJose (@OptaJose) February 21, 2026
"What we can't allow is doubt. I believe in my team. We need to maintain that level of performance over time.
"We'll keep working, pushing ourselves, and getting the best out of every player, because we need them all.
"There are many more matches to play. We have a lot of room for improvement. If you're not at 100%, anyone can beat you. Our opponents prepare very well for their matches."
Vinicius Junior scored Madrid's goal in the loss; he has been involved in 12 goals in 13 LaLiga appearances against Osasuna (nine goals and three assists), his highest tally against a single opponent in the competition.
However, Kylian Mbappe failed to get on the scoresheet for the second consecutive game.
Arbeloa was questioned about Mbappe's fitness after playing the full 90 minutes against Osasuna, and looking tired for large parts of the defeat.
"He rested last weekend; he didn't play against Real Sociedad, which wasn't just any team," added Arbeloa.
"When we think he's not fit, we're not going to take risks. It's not something I decide alone; I do it with the doctors.
"He felt ready to play, and as I said, he didn't play against Real Sociedad."