Garrido three-putted for a bogey at the par-4 18th hole, but still led countryman Miguel Angel Jimenez (67) with a 15-under total of 201. Garrido shot a course record 63 on Friday.
Garridos father, Antonio, won the Spanish Open in 1972'less than three weeks after Ignacio was born'and the pair could become the first father-son duo to win the same European Tour event.
Mark Foster of England (68), Denmarks Soren Hansen (67) and Paraguays Marco Ruiz were four strokes behind at 205.
English amateur Danny Willett was nine under through 14 before a bogey at No. 15 and three straight pars to finish with a 64'the days lowest round. He was seven shots back of Garrido.