Both players got off to flying starts at Losby Golf Club and will battle it out over the final nine holes for the honour of clinching a title that the gifted Swede Kristoffer Broberg won last year en route to The European Tour.
Fahrbring, who carded a hole in one during his course-record third round of 63, had a dream start to his final round as he eagled the par five first hole before adding another birdie at the third hole.
He stayed steady thereafter and five consecutive pars took him to the turn in three under par to remain at the summit, where he was joined by fellow Stockholm native Widegren.
The 22 year old is playing just his fifth Challenge Tour tournament and he took a step closer to a dream victory when he also started like a steam train, carding birdies in the opening three holes before another at the fifth took him to the turn in four under par 31.
Daniel Im and Johan Carlsson, another Swede, were the closest behind on 13 under par. Im was two under par through ten holes while Carlsson started with an eagle before three more birdies meant he was five under through 11.