Despite failing to win in their last four league fixtures, Rayo started the brighter of the two sides and created the game’s opening chance.
Wing-back Fran Garcia broke into the penalty area and fired a shot across goal, which needed to be parried away by Osasuna goalkeeper Aitor Fernandez – but far from intimidating the visitors, that just seemed to spur them into action.
Osasuna then enjoyed a brief period of control, and forced a double chance midway through the first period.
There was a superb cross from the left by Ez Abde which saw Rayo goalkeeper Stole Dimitrievski punch away off-balance, but the danger wasn’t averted, as the ball then fell to Osasuna midfielder Pablo Ibanez, whose shot was palmed away by the North Macedonian stopper.
With five minutes remaining before the break, Rayo scored against the run of play through a very scrappy goal.
There was a cross from the right-hand side which saw Oscar Trejo come together with Aridane Hernandez, and the last touch appeared to come off the Osasuna defender for an own goal.
There was no doubt about the home side’s second goal three minutes later though, as Palazon hooked the ball into the net from 20 yards out to give the visiting head coach Jagoba Arrasate a headache at the break.
The second half didn’t have quite the same intensity as the first, but despite Osasuna’s disappointing away form in recent weeks, with only one win from eight attempts, they were the better side in the second period.
Midway through the half, substitute Moi Gomez unleashed a left-footed strike that zoomed into the top corner to give the visitors belief of at least a point.
Despite Rayo being momentarily scared by a late header from Osasuna substitute Ante Budimir, which went inches over the bar, the Madrilenian hosts managed to prevent any further trouble.
With victory, Rayo still harbour hopes of a return to continental action after a 22-year absence, while the result dealt a significant blow to Osasuna’s European ambitions, as they lost to Rayo for the first time in six league meetings.