Blustery conditions in the Barcelona area kept a lid on the scores, which enabled Aiken to parlay his 72 into a two-stroke lead over the foursome that was tied for second heading into Sunday's final round.
The rain added to the overall gloom over the death Saturday of Spanish golf legend Seve Ballesteros.
Aiken carded a steady round of two birdies and two bogeys to keep him on track for his first win on the European Tour.
Anders Hansen was one of two players to shoot 69, which moved him into the quartet in second place.
Notable deaths of 2014 [PHOTOS]
UPI Sports Results for September 19, 2014