The hosts let a two-goal lead slip as the Portuguese's final game as coach threatened to end in disarray, but the French striker and Jose Callejon ensured no upsets late on
The Portuguese was at the centre of attention long before kick off, with throngs of photographers swarming to get a glimpse of the 50-year-old on the touchline, and first-half goals from Gonzalo Higuain and Michael Essien set him on his way to a winning send off.
Osasuna threatened to spoil the occasion with second-half strikes from Roberto Torres and Alvaro Cejudo to restore parity, but Karim Benzema put the hosts back in front before a late Jose Callejon effort sealed a victorious end to a disappointing Blancos season.
Cristiano Ronaldo was one of a number of first teamers missing through injury and suspension, as the likes of Ricardo Carvalho, Callejon and goalkeeper Jesus were pushed into the starting XI.
But Osasuna fired an early warning shot in Madrid’s direction moments after kick off when Joseba Llorente found space at the far post to angle just wide of the goal.
The visitors went even closer after a quarter of a hour, Llorente involved once again by picking out Emiliano Armanteros from the wing, but his header was met in spectacular fashion by Jesus, who tipped around the post expertly.
But despite the positivity from Osasuna, the match still struggled to get off the ground, with both teams doing little to push the tempo beyond a pedestrian level.
Madrid finally showed signs of life 25 minutes in when a mazy run from Luka Modric saw him beat two players, but was stopped at the last by Ruben, before he was about to pull the trigger.
Jesus was soon called into action again, reacting well to keep out Llorente’s low shot, after another Osasuna attacking move caused problems for the hosts.
The visitors looked far better bets to grab the first goal, but instead, it was Madrid who would strike first with 10 minutes remaining in the half.
Angel Di Maria played an excellent flick into Higuain’s path, which freed the Argentine forward to place a smart finish past Asier Riesgo.
Osasuna barely had time to regain their composure before the hosts struck again, Essien arriving first to Mesut Ozil’s corner to nod home – with the Ghanaian immediately making his way to embrace Mourinho on the touchline.
Madrid came close to extending their lead minutes into the second half, as Ozil saw a close range effort saved by Riesgo after combining excellently with Benzema inside the area.
But in the 53rd minute, Osasuna were back in the game. Torres cut in from the right-hand side, evaded the attentions of Alvaro Arbeloa, and lashed a shot into the far corner..
Callejon attempted to respond in kind with a low effort that was beaten away by Riesgo, but with over an hour played, Madrid would see their two-goal lead evaporate as Osasuna levelled the match.
David Timor set things in motion with a purposeful run and cross from the left which Manu Omwu flicked into the patch of Cejudo, who planted a firm header into the top corner.
However, parity did not last for long. With 21 minutes remaining, Benzema sent Madrid back in front, collecting Ozil’s pass at the edge of the box, shrugging off Ruben and firing expertly into the back of the net.
And with stoppage time looming, Callejon put the finishing touches on the game by getting on the end of a scintillating counter-attack to finish off the season on something of a high.