Redruth director of rugby Dave Penberthy was bitterly disappointed after his side lost 31-24 at Clifton.
Leading 16-7 at half time, Redruth went on to lose following an unusual try from James Stark.
"They went for a drop goal but it hit the crossbar, went up in the air and their guy came in and got the try," Penberthy told BBC Cornwall.
"It was a fluky finish to a terrible game of rugby. We were lethargic and went through the motions."
Brett Rule kicked three penalties and converted Paul Thirby's try in the first half, while Clifton kept in touch when Harrison Tovey crossed and Ben Roberts kicked the extras.
"We led at half-time and pulled ourselves away, but it was a poor performance in the second-half, we just went through the motions," Penberthy said.
"Decisions that went our way in the first-half went against us in the second. I don't know what [Clifton coach] Mark Regan said to the referee at half-time but it worked.
"We found ourselves under a lot of pressure and we ended up losing the game."
Rule extended the lead with another penalty after the break, but William Pomphrey's try kept the hosts in touch.
They stormed into the lead when kicked a penalty soon afterwards, before Jack Gadd went over to put his side ahead for the first time.
Thomas Notman's try drew Redruth level, but Rule missed the conversion to allow James Stark to grab the winning try in unusual circumstances.
"We could have won it and we should have won it. We were in control of our destiny and we screwed it," Penberthy concluded.