Uxbridge assistant boss Paul Mills thinks his team were denied a perfectly good goal to deny them an FA Trophy replay with Didcot Town.
Kevin Warner looked to have snatched a 2-2 draw at the death only for the officials to have adjudged the ball had not crossed the line.
It left boss Tony Choules and his staff gutted at the final whistle as they crashed out of the competition at the second qualifying round.
Mills said: “From where we were it looked like it crossed the line, but we’re very far away and it’s tough with so many bodies in the box.
“The first two goals gave us a mountain to climb, but we feel hard done by. We’ve always got goals in the side, but these individual errors are costing us games.”
The Reds made a quick start and Matt Woods could have scored twice in the first five minutes at Honeycroft on Saturday.
Then, after 15 minutes came the game’s turning point, as a clumsy Adam Pepera foul in the box gave the Oxfordshire side a penalty, which John Mills converted.
Uxbridge found themselves under the cosh and Didcot double their lead courtesy of captain Luke Carnell, who was impressive all game at the heart of the visitors’ defence.
Choules' side were indebted to goalkeeper Rourke Pickford for keeping them in the game at times during heavy pressure.
The second period certainly signalled an improvement but when Dave Thomas was sent off for a second yellow eight minutes from time the game looked up.
However, a Chris Moore tap-in then set up a thrilling climax.
And with almost the last kick of the game Uxbridge thought they had forced a replay only for the officials to have judged that the ball did not cross the line.
Having missed out on the £3,200 prize money for qualifying for the next round, Uxbridge’s focus will now turn to the league as they face Bedworth United at home on Saturday.
Northwood were also knocked out of the Trophy by a 2-1 scoreline at the weekend as Dave Lawrence’s late strike was not enough to save them against Wimborne Town.
Mark Burgess’ team could not cope without the loss of top scorers Ismael Ehui and Nana Asamoah up front.