Peter Uihlein carded a 4-under 68 on Friday and grabbed the lead through two rounds of the Open de Espana.
Uihlein, the only American in the field, sits at 6-under 138 through 36 holes -- one shot clear of first-round co-leader Felipe Aguilar (71), Raphael Jacquelin (66) and Rikard Karlberg (67).
"I am very pleased with the way I played," said Jacquelin. "Even yesterday, I shot 1-over but hit the ball pretty good."
Before Uihlein finished, Karlberg was alone in first place at minus-7 through 14 second-round holes, but he closed with back-to-back bogeys to fall back to 5-under.
First-round co-leader Morten Orum Madsen shot an even-par 72 on Friday. The Challenge Tour graduate is tied for fifth place with rookie Eddie Pepperell (70), Marc Warren (70), Craig Lee (71) and Andreas Harto (67) at minus-4.
David Howell (71), Lasse Jensen (70), Tommy Fleetwood (69) and Matthew Baldwin (68) are knotted in 10th place at 3-under, while world No. 31 Gonzalo Fernandez-Castano (73) is part of a large group tied for 14th at minus-2.
"I didn't play as good as yesterday, but overall I'm in a good position for the weekend," said Fernandez-Castano.
Gary Stal, the other first-round co-leader, made the cut on the line at 2-over after stumbling to a second-round 78. Sergio Garcia made it through to the weekend at 1-over through 36 holes, but defending champion Francesco Molinari never found his form and ended two rounds at 7-over 151.
Madsen, Pepperell and Warren went out with the early wave and grabbed the clubhouse lead, but the advantage proved fleeting.
Seeking his first European Tour win, Karlberg made a significant run at the top spot, opening with three birdies and an eagle in his first four holes. He closed with an outward 31, then picked up birdies on Nos. 11 and 14 to reach 7-under.
But Karlberg couldn't hold the lead. He picked up a pair of pars, then bogeyed both the 17th and 18th to drop into a tie with Aguilar and Jacquelin, who was 6-under before a bogey on No. 17.
"I did well today," added Jacquelin. "It was great to play; I think maybe it was a little more windy this morning, but sometimes you have to be lucky."
Uihlein, who is playing on an invitation this week, was one of the last to finish and he waited until the end of his round to jump ahead. The American was 1-under on his round through 10 holes courtesy of three birdies and a pair of bogeys, but he closed with a flourish, picking up three birdies in his final five holes to grab the outright lead.
NOTES: This is the fourth time that Parador de El Saler is hosting the tournament, but the first since 2001 ... Aguilar had missed the cut in his previous three starts. He finished inside the top 10 in his four events prior to that streak ... Madsen and Stal are both graduates of the Challenge Tour ... Matteo Manassero turned 20 years old on Friday and made the cut on the line.