Valencia were held at home by a spirited Zaragoza side, who were given no favours by the officials.
Despite lining up in a 5-4-1 formation, bottom side Zaragoza took a shock lead in the second minute. Jiri Jarosik found Maurizio Lanzaro who remained onside and half-volleyed the ball into the net past Miguel Moya, which stunned the home crowd.
Sustained pressure brought Valencia's equaliser when Lanzaro turned villain as he headed a Juan Mata cross into his own net after a breakdown in communication with Toni Doblas.
Los Che almost hit back immediately when Ricardo Costa's effort struck the post three minutes later. Mehmet Topal had a further chance when he checked his run sufficiently to latch onto the ball but Doblas made an excellent sprawling save to deny the Turkish midfielder.
Eight minutes after the break, the alarm bells were ringing for Zaragoza when Vicente's free-kick was headed back towards goal by Topal but fortunately for the out-of-position Doblas, Jarosik was on hand to hack the ball clear from the goal-line.
Zaragoza's task became a great deal more difficult after 67 minutes. Substitute Ander received a straight red card for a trip on Juan Mata. Incredibly, it was the fourth game in succession that they had been reduced to ten and in this instance, they were hard done by.
The officials did not endear themselves to a visiting side in need of a rub of the green. With eight minutes left, Braulio thought he was about to win the game when he rounded Moya but was wrongly adjudged offside.
Valencia came with the inevitable late bombardment in order to force a winner. Juan Mata danced into the penalty box but just as he pulled the trigger, he was thwarted by an excellent sliding block from Carlos Diogo.
The draw leaves Zaragoza still at the bottom of the table but now tied on points with Deportivo. Valencia's stumble keeps them in fourth place but opens up the possibility of Unai Emery's side being overtaken by Espanyol.