Osasuna have scored fewer goals than any other Primera Division side this year and boast the joint fourth tightest defence, so when Sola rose in the box to head in a cross from Abella Damia and score with less than four minutes gone, it was no surprise that they chose to sit back for the rest of the game and attack with caution.
The visitors had far more possession but were outmuscled by their opponents and although they had marginally more attempts on goal, it was the hosts who looked more likely to score.
Zaragoza's best attempt came late in the first half, with Ruben Rochina getting on the end of a cross by Fernandez Abraham but his effort was superbly turned away by Osasuna goalkeeper Andres Fernandez.
The hosts came closest to doubling their lead through substitute Francisco Silva, who tried to lob Jimenez Roberto after a pass by Emiliano Armenteros, but the Zaragoza goalkeeper stood tall to make the save.
The three points means that the Navarrans overtake Zaragoza in the Primera Division table, but things are looking grim for Manolo Jimenez's side - they have not won in their last seven games in the league and now occupy 17th place, the last position above the relegation zone.