The Portugal international, who netted Madrid’s first as they twice came from behind, rose to bury Gonzalo Higuain’s far-post cross just as it seemed the plucky visitors had done enough.

Marcelo was also on target for the hosts, while Carlos Aranda and Krisztian Vadocz scored for the Pamplona-based side.

A frantic and entertaining first half yielded four goals, although they were as much the result of comic defending as attacking intent.

Madrid defender Raul Albiol was the first to showcase his ineptitude, air-kicking a straightforward clearance to let former Merengues trainee Aranda run through, round Iker Casillas and tap into an empty net for an early Osasuna lead.

His team-mates rallied, with Ronaldo shooting just wide and Ricardo saving from Kaka, and they drew level when Osasuna’s defence inexplicably showed the Portugal star inside, backing off him all the time as he steadied a low drive inside Ricardo’s near post.

Esteban Granero had a shot deflected wide, while down the other end Aranda headed straight at Casillas from 10 yards out and a Javier Camunas free-kick wreaked havoc in the Real box.

The visitors took the lead a second time when, on 42 minutes, Aranda took a long throw on his midriff, turned and fed Hungarian midfielder Vadocz who evaded a non-challenge from the admiring Xabi Alonso before thrashing a superb finish into the top right.

It did not take long for Real to level, with more slack defending allowing little Marcelo - standing at under 5'8” - to rise above the visiting backline to head Granero’s lofted pass into the bottom right.

Ronaldo and Granero had efforts fly just wide before the break as Madrid looked to seize on their impetus at the start of the second period.

From kick-off Gonzalo Higuain ran through on goal and was denied by Ricardo, while four minutes later the Portuguese shot-stopper bravely denied Kaka after he spilled Ronaldo’s shot.

Granero then fired a left-foot drive over after being shown inside and unchallenged as for Ronaldo’s goal, while Osasuna really should have taken the lead for a third time after spurning two gilt-edged chances.

First Aranda blasted over from point-blank range after Casillas had saved his initial close-range effort, while the visitors somehow spared Madrid when - after springing the offside trap - Camunas bizarrely opted to play the ball across to Masoud Shojaei, with the Iranian slipping as he stretched into a finish that trickled embarrassingly wide with the keeper floundering.

Those misses woke Madrid up and they dominated the closing quarter hour.

Substitute Karim Benzema fired straight at Ricardo from point-blank range after Ronaldo’s scintillating run down the right, while Marcelo was denied a spectacular volley by the Osasuna shot-stopper.

The ex-Manchester United keeper was in fine form, batting out a Ronaldo drive and flying about to tip away and parry crosses from wide as Madrid pressed for a winner.

But he was powerless to deny Ronaldo when, after Higuain did exceptionally well on the left, the 2008 World Player of the Year arrived unmarked to power his header into the bottom right.

Sevilla claimed a crucial 3-1 win over Atletico Madrid to briefly overtake Mallorca in the race for La Liga's fourth Champions League spot.

Mallorca moved back into the top four later on Sunday after they won 3-1 at Athletic Bilbao.

A blistering start to the match saw three goals in the opening 12 minutes, and the home side twice taking the advantage. Atletico yielded the opening goal with just four minutes played, failing to deal with a corner and leaving Luis Fabiano free to tap-in at the far post.

If the sluggish start was a hang-over from the away side's mid-week Europa League exertions against Liverpool, Fabiano's goal quickly snapped them out of it as they stormed back into the match straight from kick-off.

Having won a free kick just inside Sevilla's half, Jose Antonio Reyes curled a pinpoint delivery into the far post to Nacho Camacho. The Spaniard then headed the ball back across goal for Tiago to slam home past the helpless Andres Palop.

The parity was well deserved, but wasn't to last long as, just four minutes later, Valera clattered in to Adriano just inside the area, leaving the referee no choice but to point to the spot.

Alvaro Negredo stepped forward to slot the ball expertly inside David De Gea's right post, and again snatch the lead for the home side.

The goal knocked the stuffing out of the visitors, who went on to concede a second penalty in the 38th minute thanks to some more ill-disciplined defending, this time by captain Luis Perea, who hauled down Abdoulay Konko trying to defend a corner.

Negredo stepped up again, and this time sent the penalty to the keeper's left, with the same emphatic result.

The visitor's threatened a response late in the first half, with the much-lauded Sergio Aguero jinking into space on the left before delivering a dangerous ball across Sevilla's goal.

With Palop only able to palm the ball to Reyes, the Spaniard could only fire the ball into the post and clear.

Atletico came out fighting in the second half, with Reyes and Aguero in particularly menacing mood.

A propensity to take too many touches proved fatal to the visitor's hopes of getting back into the match, though, and it was Sevilla who threatened to increase their lead.

The increasingly dangerous Jesus Navas forced a corner for the home-side, which Federico Fazio met with a towering header, which cannoned back off the bar.

It would prove to be the final clear-cut chance of a much more competitive half, with Sevilla claiming a vital three points to keep their hopes of Champions League qualification alive.

At the San Mames, Mallorca schooled Athletic in the art of counter-attacking with a 3-1 win.

Athletic had more chances and possession but Mallorca were more ruthless and won thanks to goals from Chori Castro, Nunes and Aritz Aduriz.

Fernando Llorente was on target for the hosts with a trademark header.

Defet means Athletic cannot qualify for the Champions League, although they have a Europa League slot to chase.

Mallorca stay two points ahead of Sevilla with two games left.

Reda Maher / John Stead / Eurosport