COBRA came from behind to claim a vital victory and all but end Llanidloes’ hopes of promotion.
With one game remaining until the split COBRA kept themselves in the top three, by outscoring their hosts after trailing early on.
Llanidloes held the upper hand when outside-half Dan Short kicked three penalties inside the opening quarter.
COBRA held their nerve and replied on 30 minutes, as a missed pass allowed full-back Geraint Williams to free wing Matthew Jones, who set up wing Ifan Evans to crash over.
COBRA were now in the ascendancy and took the lead when prop Andy Evans broke through and released flanker Alun Jones, who sprinted clear to score with Williams adding the conversion.
On 55 minutes COBRA forced a turnover and moved the ball wide to centre Sion Wyn Williams, who scythed through the defence to score.
COBRA continued to pile on the pressure, but wasted two clear try scoring chances and a pair of penalties.
With five minutes remaining the reliable Short reduced the arrears for Llanidloes with his fourth penalty of the day.
However they were unable to find the try they needed as COBRA held firm to all but seal promotion.
LLANIDLOES: H Owen, Jehu, E Pugh, B Davies, Goodman, Short, I Jones, Murray, Savage, N Hamer, R Jones, I Jones, B Hamer, D Jones, Mills. Reps - J Evans, D Hughes, Plumridge, Annwyl
COBRA: A Roberts, C Davies, A Evans, R Vaughan, H Evans, A Davies, A Jones, B Jones, I Vaughan, R Davies, I Evans, A Pryce, SW Williams, M Jones, G Williams. Reps - Oakley, G Evans, Griffiths, F Roberts