The visitors began brightly and broke the deadlock in rather subdued fashion, as Diego Lopez initially thought he had mistimed his run from Ivan Jaime’s long ball before rounding Sergio Herrera and slotting the ball into an empty net.
However, a VAR review confirmed that the 22-year-old was onside to give Valencia a surprise lead.
That joy was short lived though, with parity restored a mere 12 minutes later when Ante Budimir lost his balance when latching onto Bryan Zaragoza’s pass, but still managed to lay the ball on a plate for Aimar Oroz to coolly slot home from close range.
This topsy-turvy contest then took another twist to silence the home crowd once again, as Umar Sadiq showed brilliant tenacity to slide home from Javi Guerra’s cross.
But Osasuna responded yet again in a breathless first half, with Aimar netting his second with a superb volley which he hit into the turf before it flew past Giorgi Mamardashvili.
The action was not done there, and referee Mario Melero pointed to the spot after Cristhian Mosquera brought down Rubén Garcia in the box.
Budimir stepped up to score a history-making goal from the spot, becoming Los Rojillos’ all-time record goalscorer in La Liga with 58 goals and surpassing Sabino’s record.
Carlos Corberan’s side responded well after the break, and Luis Rioja was looking particularly lively in a Valencia side searching for a third goal.
His long-range effort was kept out by Herrera at the near post, before a separate attempt flew just wide of the target.
Valencia continued to have the better of the limited second-half opportunities, with Cesar Tarrega heading wide from Pepelu's searching set-piece.
But Valencia claimed the goal their second-half endeavour deserved when Sadiq produced an audacious backheeled finish from Guerra’s cross to bring the visitors back onto level terms.
Ultimately, the spoils were shared to leave Osasuna with only one win from their last 14 games in Spain’s top flight.
Meanwhile, the nature of the draw may feel like a victory for Corberan’s team, but this result extends their winless run on the road to 16 away league games for the first time since 1983.
Los Ches move up one place into 18th, but a first relegation since the 1986/87 campaign remains a genuine threat for one of the country’s biggest clubs.
Flashscore Man of the Match: Umar Sadiq (Valencia)