Kylian Mbappe sent the reigning champions ahead in the 15th minute when he turned a cross from Federico Valverde into the back of the net.
However, Los Blancos were reduced to 10 men in the latter stages of the first period, with Bellingham handed a straight red card for dissent after an exchange with the referee.
Osasuna levelled the scores from the penalty spot just before the hour through Ante Budimir, and Real Madrid were unable to respond, with the points ultimately being shared at the conclusion of a tense affair at El Sadar.
Real Madrid are now two points clear of second-placed Atletico Madrid at the top of the La Liga table, while the point is enough to move Osasuna into seventh, just three points behind sixth-placed Rayo Vallecano in the race for Europe.
SPORTS MOLE'S VERDICT
The referee's report after the match will disclose what was allegedly said to him by Bellingham, but it is clear that Real Madrid were left furious by the decision to hand the midfielder a straight red card.
At 1-0, Los Blancos were in control, and it did appear that they would be moving four points clear at the top of the table and cementing their spot at the summit for at least another round of fixtures.
However, Atletico will now have the chance to move above them on Saturday evening, while Barcelona can also go ahead of the reigning champions if they are able to overcome Rayo Vallecano on Monday night.
There is no getting away from the fact that this was a setback for Real Madrid, but they did show character to play that long for 10 men and avoid suffering a fourth league defeat of the campaign.
After all is said and done, this point could be valuable for Carlo Ancelotti's side at the end of the campaign.
OSASUNA VS. REAL MADRID HIGHLIGHTS
25th min: Osasuna 0-1 Real Madrid (Kylian Mbappe)
Real Madrid make the breakthrough in the 15th minute of the contest, and it is Mbappe again, with the Frenchman converting a brilliant low cross from Valverde to silence the home supporters at El Sadar.
39th min: Jude Bellingham (Real Madrid) red card
Los Blancos are reduced to 10 men in the closing stages of the first period here, with Bellingham given a straight red card by the referee for dissent - it is unclear what was said, but the referee went straight to his pocket.
58th min: Osasuna 1-1 Real Madrid (Ante Budimir, penalty)
Osasuna level the scores from the penalty spot just before the hour, with Budimir converting past Real Madrid goalkeeper Thibaut Courtois after Eduardo Camavinga was adjudged to have fouled Budimir inside the box.
MAN OF THE MATCH - KYLIAN MBAPPE
Mbappe has found his feet at Real Madrid after a tough start to his Los Blancos career, and the Frenchman was again on the scoresheet on Saturday, firing a low Valverde cross into the back of the net.
The 26-year-old had eight shots in total and could have had a couple more on another afternoon, while he completed five successful dribbles, with Osasuna finding it so difficult to deal with the former Paris Saint-Germain attacker.
OSASUNA VS. REAL MADRID MATCH STATS
Possession: Osasuna 45%-55%% Real Madrid
Shots: Osasuna 11-17 Real Madrid
Shots on target: Osasuna 4-5 Real Madrid
Corners: Osasuna 6-2 Real Madrid
Fouls: Osasuna 16-7 Real Madrid
BEST STATS
WHAT NEXT?
Real Madrid's attention will now switch back to the Champions League, preparing to welcome Manchester City for the second leg of their knockout round playoff on Wednesday evening, and Los Blancos have a 3-2 advantage in the contest.
Ancelotti's side will then return to La Liga action at home to Girona next Sunday, while Osasuna will be bidding to stretch their unbeaten run in the league to six matches when they travel to Celta Vigo on Friday night.
Written by
Matt Law