Suneson walked into the final round with a one-shot lead and his 2-under-par 69 on Sunday was good enough for a three-shot win. He finished at 8-under-par 276 to top three players at the Val Course at Aa Saint Omer Golf Club.
Marcus Higley, who began the day in second place, could do no better than an even-par 71 on Sunday. He tied for second with Francois Calmels (69) and Peter Fowler (70) at 5-under-par 279.
Mikael Lundberg managed an even-par 71 on Sunday and took fifth place at minus-4. Michael Lorenzo-Vera shot a 1-under 70 for sixth at 3-under-par 281.
Suneson's one-shot cushion quickly became two after Higley bogeyed the first hole. Lundberg and Calmels would also pull within two, but Suneson stayed steady with six consecutive pars to open his round.
Suneson, a five-time winner on the Challenge Tour, birdied the par-5 seventh hole for the second time this week to extend his advantage to three shots.
'I was also lucky that no one was attacking me,' acknowledged Suneson. 'I was leading by one and Higley made bogey on the first and I just told myself to wait for the birdie to come because I don't have to force any situation.'
That lead was short-lived as Suneson gave one back with a bogey at the eighth. Luckily for Suneson, none of his closest competitors could make any birdies to close the gap. Suneson's lead never fell below two after the bogey at eight.
Suneson missed a chance to go lower when he parred the par-5 ninth, but did reclaim his three-shot margin with a birdie at 12. Higley birdied 13 to claw within two, but Suneson responded. He birdied the 14th and once again found himself three clear.
Calmels and Fowler joined the mix at 5 under par, but Suneson birdied No. 17 to take a commanding four-shot lead on to the final hole.
He ended up with a bogey at the last which only hurt his final margin of victory.
'I am delighted to win, it is a fantastic feeling to win,' said Suneson. 'It's unbelievable, to have led going into the last round and to get through it is amazing.
'I played well today and I couldn't believe how I felt. I don't know who was helping me out there because I felt very calm.'
Stuart Davis (73), Sebastien Delagrange (70) and Richard McEvoy (69) shared seventh place at minus-1.
Daniel Denison (71), Klas Eriksson (69) and Gareth Paddison (72) tied for 10th at even-par 284.