Rafa Cabrera Bello and Adri Arnaus share the halfway lead in the Mutuactivos Open de Espana as Gavin Moynihan, Michael Hoey and Paul Dunne all missed the cut.
Cabrera Bello, who has yet to drop a shot in Madrid this week, added a second round of 65 to his opening 66 to finish 11 under par alongside Arnaus, who looked set to hold the outright lead until a bogey on the last in his 66.
World number 1,413 Samuel Del Val is just a shot off the lead after a superb 65, with world number five and defending champion Jon Rahm a stroke further back on nine under following a 67, making it an all-Spanish top four.
Cabrera Bello, whose last European Tour title came in the 2017 Scottish Open, said: "You don't get to go bogey-free very often and to do it two days in a row, I don't know how many times I've done that.
"I'm obviously very pleased with the way I'm playing. I'm feeling very confident out there, in control of my game and when I get into trouble my resources manage to save par."
Cabrera Bello played alongside Arnaus and Rahm in the first two rounds and added: "Yesterday was like a dream day and today we had it again. I think we're minus 31 for the three of us which is remarkable.
"We've just been feeding off each other and the crowd. To have thousands of people cheering for us has been really cool."
The cut mark for the weekend was even par. Moynihan carded four over for his two rounds, with Hoey and Dunne plus six to end their involvement.
Del Val, who carded seven birdies and a solitary bogey in his 65, is contesting his 22nd tournament in the space of 28 weeks as he tries to secure his playing rights somewhere for next season.
"I felt like I controlled both rounds really well, didn't really make many mistakes," the 32-year-old said. "I had the putter going both days and I'm in a really good position for the weekend.
"I didn't feel like the course would suit my game too well but I've been smart around it, I've left the ball on the right side of the greens so the ups and downs were not as hard. It seems like it's been easy golf so far."
Spanish Ryder Cup star Sergio Garcia is seven shots off the lead after carding a second consecutive 69.