كتب : Ahmed Saied
Arruabarrena's finish in the 49th minute cancelled out a Rangers' early lead through Peter Lovenkrands.
The result left the aggregate tie 3-3 but the Spanish side advanced due to the away-goal rule as they scored twice in Scotland.
Lovenkrands opened the score line in the 12th minute when he poked home on the rebound after the home keeper parried a shot from parry Buffel into his path.
Villarreal grabbed the equalizer when Rangers defense and keeper failed to clear Diego Forlan's neat cross that Arruabarrena sent home.