Kilwinning boss David Gormley was left ruing 'fine margins' as Forfar brought an end to the West of Scotland League outfit's first-ever Scottish Cup adventure.
Tomas Brindley's superb first half strike and a bizarre Dominic Boland own goal had the visitors 2-0 in front after 64 minutes of Saturday afternoon's second round tie at Buffs Park.
But the League Two side never had it easy at any stage and were made to sweat when Thomas Collins' diving header halved the Loons’ advantage in the dying stages to raise hopes of a grandstand finish.
Unfortunately for the hosts, Forfar frontman Matthew Aitken struck in stoppage time to quickly kill off any chance of a fairytale ending.
Gormley admitted it had been a frustrating afternoon in front of goal but insisted he couldn't have asked for much more from his players.
He told Ayrshire Football News: "The first half, I thought we were the better team throughout. I was happy with the performance.
"The second goal is a body blow. When that goes in it sucked the life out of the boys.
"It's fine margins when you're playing against higher opposition.
"It was just one of those days for us where I thought we were never going to score. It was a frustrating afternoon in terms of our final product.
"I feel for the boys because they put a good shift in and they did what we asked of them, on and off the ball.
"I'm disappointed we're out the cup but it was a free-hit for us."
Kilwinning started confidently and had Forfar on the back foot for most of the opening 15 minutes without really troubling goalkeeper Marc McCallum.
The visitors were then forced into an early change with injured captain Craig Slater replaced by Callum Moore.
Kilwinning kept the pressure on but their momentum was disrupted by a five-minute stoppage in play to fix a hole in the home net.
Forfar came more into the game once play resumed and they should've got their noses in front in 23 minutes.
Aitken's superb cross-field pass sent Stefan McCluskey in behind the Buffs back-line and his attempted lob over advancing goalkeeper Craig Gordon dropped just the wrong side of the crossbar.
Gordon was called into action again soon after, parrying Moore's low drilled effort then quickly smothering the loose ball with Jaden Ferguson poised to pounce.
The keeper could do nothing to stop Brindley from opening the scoring in 27 minutes however - the midfielder finishing off a darting run into the box with a powerful strike that found the top corner.
McCluskey was presented with a carbon copy chance on the hour mark but his daisy cutter was batted away by Gordon.
Kilwinning weathered the mini-storm to finish the half strongly, Collins thwarted by Roberto Nditi's excellent blocking tackle in 41 minutes as he looked to sweep home a Dylan Mackin cross.
It was still all to play for in the second half, and while Buffs continued to show plenty of endeavour, it was Forfar who created the better goalscoring opportunities.
McCluskey lobbed Gordon for a second time in 57 minutes only to see Marc Millar make a brilliant headed goalline clearance over the bar.
Two minutes later, Aitken scrambled the ball home to seemingly double the visitors' lead but the goal was eventually chopped off for offside after a long deliberation between the referee and linesman.
Forfar would not be denied a second however - even though it arrived in almost comical circumstances in 64 minutes.
Kilwinning defender Dominic Boland played a blind passback from the flank which caught Gordon completely off guard and despite the keeper's best efforts to divert the ball away from goal, he succeeded only in helping it into his own net.
It was a real tough one to take for the hosts but they continued to battle away. Mackin sent a glancing header wide of the target, then saw a more powerful effort denied by a fine reflex save by McCallum.
The keeper had no chance with Collins' close range diving header in 89 minutes but any jangling nerves were eased shortly afterwards when Aitken raced on to Joshua Jack’s slide-rule pass and slotted under Gordon to complete the scoring.
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