Twente stretch lead with Friday night win
Wesley Verhoek opened the scoring for ADO in the first minute before Ruiz levelled with a penalty.
Costa Rican Ruiz added his second, and 19th league goal of the season, 11 minutes into the second half when Luuk de Jong set him up from a counter attack. Kenneth Perez then sealed victory.
Steve McClaren's Twente have 70 points from 27 matches, five more than PSV Eindhoven who play their game in-hand at third-placed Ajax Amsterdam on Sunday.
ADO are third from bottom.