Redruth boss Marek Churcher says his team were disappointed despite picking up a bonus point against Barnes.
The Reds' 26-20 victory was their fifth in six games and saw them consolidate fourth place in National Two South.
They were 19-5 ahead, but Barnes came back to lead 20-19 in the second half before Redruth re-asserted control.
"We're really disappointed with our performance, but to be disappointed even though five points is probably a positive thing," said Churcher.
"There's something in there, I don't know what it is, I'm not sure if it's coachable or uncoachable, but we've just got to play for 80 minutes and trust those systems.
"We'll pick the positives up, we had some outstanding individual performances, but we've got to march on now and move forward."