Despite winning just once in their last six matches the Pamplona outfit are eighth in the standings on 48 points, and can still fight for a spot on the Europa League.
Valencia thrash 10-man Osasuna 4-0. Photo: EFE
Valencia were looking to put their miserable recent run behind them to secure a third-placed finish over the final weeks of La Liga.
Unai Emery's men went into Wednesday's home game with Osasuna having lost four of their last five fixtures, two of which saw them dumped out of the Europa League semi-finals by Atletico Madrid, and the other came at the hands of top-four rivals Malaga last weekend.
That 1-0 loss at La Rosaleda saw Malaga move level with Valencia on 55 points, although the latter still managed to retain third place due to their better head-to-head record against the Andalusian side this season.
Valencia will now attempt to keep hold of that berth in their final three games, which sees them hosting Osasuna and Villarreal before going to Real Sociedad on the last weekend.
Osasuna, who travelled to the Mestalla still in with a chance of securing European football themselves next season, finished the first half with 10 men after Dejan Lekic was shown a straight red card for striking Adil Rami in an off-the-ball incident as the half time whistle was being blown.
Despite winning just once in their last six matches the Pamplona outfit are eighth in the standings on 48 points.
And they succumbed in the second half, despite the efforts of goalkeeper Andres Fernandez. After making a fine save to deny Brazil international Jonas, the defence in front seemed to let Fernandez down.
It wasn't until the 77th minute that Valencia finally managed to breach the Osasuna defence. Some slick one-touch football saw Jordi Alba pull the ball back and Aritz Aduriz rose to head the hosts into a 1-0 lead.
Six minutes later it was 2-0 and Jonas found enough room at the far post to fire past Fernandez. Valencia were now rampant and they hit the back of the net for a third time in just ten minutes.
Aduriz was on the mark again, this time running through to meet a cross from Pablo Piatti. The home side weren't finished with the late scoring and a fourth came a minute after the third.
Jonas completed his brace by knocking in a rebound from close quarters after Fernandez had parried an initial shot.
The 4-0 result, combined Levante's defeat to Real Zaragoza, meant that even should Emery's side now lose their last two fixtures, their local rivals cannot overtake them as Los Che hold the better head-to-head record from their two league meetings this season.