Redruth won their first Cornish derby for more than two years to heap further misery on struggling Launceston.
In a messy game at the Rec, the Reds ran in two first-half tries - Jack Nowell and Steve Wood the scorers.
Launceston threatened a comeback in the second-half but failed to convert their pressure into points.
Redruth kept pressing and were rewarded with a late Mark Bright try to seal the win that puts them 13 points clear of Launceston in the relegation battle.
Launceston remain bottom-of-the-table with just seven points, 15 adrift of safety.
The Reds' victory moved them up to third-from-bottom on 20 points, leapfrogging Cinderford who have 18.
With National One survival at stake for both sides, the Reds proved the stronger in the opening exchanges, enjoying the majority of possession as Launceston struggled to gain a foothold in the match.
A prolonged period of pressure on Launceston's line led to the Reds' first-try, as the visitors' defence disappeared allowing full-back Knowle to power over.
The second touchdown was also created by the Reds pack, who drove flanker Wood over from an attacking lineout to put the side 13-0 up at half-time.
Launceston's best chance came shortly after the restart, but winger James Hawken spilled the ball as he prepared to put it down over the Reds line.
Reds fly-half Aaron Penberthy proceeded to take the game away from their rivals, with a second penalty and drop goal, before Bright rounded off a fantastic afternoon for the West Cornwall club with a try in the dying seconds.
Redruth director of rugby Dave Penberthy told BBC Radio Cornwall: "2008 was the first derby win, and so it's nice to get the second.
"The downtime has worked in our favour. I think we were getting into a losing habit, but we've had a break, brought the team together and worked and worked.
"The players were chomping at the bit to have a game of rugby as well."
Launceston captain Tom Rawlings told BBC Radio Cornwall: "We seem to think that we can go out in the second half and win games, but there's two halves to a game and we didn't play in the first.
"We picked our level up in the second half but it still wasn't good enough and we've got to have a real look at ourselves in the mirror over Christmas.
"I think we were probably trying a little bit too hard, we should have calmed our game, gone to our strengths and maybe used our forwards a little bit more."
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