Home hope Rafael Cabrera-Bello will take a two-shot lead into the final round of the Spanish Open after firing a seven-under-par 64 on Saturday, as world number one Jon Rahm slipped six strokes off the pace.
Spaniard Cabrera-Bello, who has fallen to 231st in the world rankings after a torrid run of form, carded a bogey-free round in Madrid to give himself an excellent chance of a fourth European Tour title.
Cabrera-Bello moved to 17-under for the tournament.
"It would be amazing (to win)," he told europeantour.com. "I've won every Spanish amateur title there is and I'm missing this one which would be the pinnacle of Spanish golf.
"I'm going to have a very good chance at it tomorrow but I'm sure there'll be more chances in the future too so I'll just go out there, have fun, feed off the crowd and try to put on a show for them again.
"Today was one of my favourite days ever out there, in front of my countrymen, playing on a course that I love and with beautiful conditions, I felt really good."
Adri Arnaus and Frenchman Julien Guerrier are two shots back in second, but Rahm dropped back.
The US Open champion, chasing a third straight Spanish Open title, stumbled to a one-over 72 despite a birdie on the 18th hole.
Rahm is in a tie for ninth on 11-under.