Windy conditions made life difficult in County Antrim, and Aberg was playing catch up from the off after he bogeyed the par-four first hole.
He then bogeyed the third and, despite recording a birdie on the seventh, he was back to two-over for the round with his third bogey on the front nine on the ninth.
The 25-year-old had a more solid back nine, with registering one more birdie before a fourth bogey, which came on the par-three 16th to complete a 73-shot round. Overnight, he sits tied for 70th on the leaderboard, with many players hoping to catch the five players level at the top on -4.
The Swede who had the best opening round was Jesper Svensson, who sits tied-32nd after a level-par first 18 holes.
It could have been better for the world number 135, who was sitting on -2 after the first eight holes, but three bogeys in the next four holes halted the strong start. Birdies on the 16th and 17th got the 29-year-old back up the leaderboard, before he finished with another bogey to finish as he started.
World number 760, Jesper Sandborg, finds himself nestled between Svensson and Aberg at +1. Sebastian Soderberg completed the opening round at +2, while veteran Henrik Stenson is a further two shots back.