Real Madrid failed to build on their impressive clasico victory after being held to a goalless draw by Osasuna in La Liga on Wednesday.
Three days after eclipsing rivals Barcelona at Camp Nou, Real failed to reproduce the fireworks against high-flying Osasuna.
The team from Pamplona keep on defying the odds and are now sixth in La Liga, only two points behind Real, Sevilla, Betis and Real Sociedad, the four clubs tied at the top on 21 points.
Osasuna also sit four points above Barcelona, who slumped to their second successive league defeat on Wednesday following a 1-0 loss to Rayo Vallecano that cost coach Ronald Koeman his job.
Real dominated possession but were repeatedly frustrated by Osasuna, who played with 11 men behind the ball, and their gamble paid off as they left the Bernabeu with a point.
Osasuna, who have only lost twice in 11 league games this season, are now unbeaten in their last five La Liga matches.
"People will say that I'm crazy but I liked the game and I think our team played well but couldn't find a way to score", said Real coach Carlo Ancelotti.
Madrid lead the table on goal difference after 10 matches and the Italian predicts a closer title race than in previous campaigns.
"La Liga is very even, there are lots of teams up there. I don't think it's going to take 100 points to win it this season," added the Italian.
After a frustrating first half, Ancelotti brought on Rodrygo in the hope of opening up more scoring chances. But his presence failed to make any difference.
Real were almost caught off-guard in the 50th minute when a Jon Moncayola strike ricocheted off the post while at the other end Karim Benzema also hit the bar following a cross from Vinicius Jr.