The Challenge Tour graduate, fresh from his first top five finish on the European Tour at the Austrian Open, made five birdies and an eagle at the long third to race to the turn in 29.
Any thoughts of breaking 60 were put on hold when the 31-year-old bogeyed the tenth, but Garcia Rodriguez then fired to five feet at the 13th and made it back-to-back gains at the next.
A second bogey of the day came at the 16th but the European Tour rookie recovered in style with an eagle on the 17th from ten feet before adding a birdie at the last from similar range for good measure.
“For me it's incredible but the key thing is the driver,” said Garcia Rodriguez. “The putts were so close to the hole all the time.
“It's amazing, it's my first low, low score on the European Tour.”
Scotland's Connor Syme and English pair Laurie Canter and Matthew Southgate were then a shot further back in the clubhouse, with Belgian Thomas Detry also on five under with three to play after holing his approach to the 14th.