Ben Woods scored two tries as Old Belvedere gave their hopes of avoiding relegation a massive boost by securing a bonus-point victory over the recently crowned champions at Lansdowne Road.
The hosts opened the scoring with a 16th-minute penalty but the Anglesea Road men crossed the whitewash through the influential Woods on 23 minutes, with Josh Glynn converting.
Lansdowne, however, finished the half in fine fashion with an unconverted try by Conor O'Donnell and a drop-goal from Sean Carey. That gave Mike Ruddock's charges an 11-7 cushion at the break, but this was reduced six minutes in with a penalty from Glynn.
Belvo deservedly regained the lead with 13 minutes to go when Glynn registered a seven-point salvo, and with Fergal Lawlor adding a drop-goal, a much-needed win was in their grasp.
A third try from Leo Auva'a helped to seal their triumph, and even though Willie Earle reduced the gap with a try on the stroke of 80 minutes, Woods pounced again in the dying seconds.
LANSDOWNE – R McCarron; C Aherne, S Carey, S Morrissey, C Toolan; C Ronaldson, P O'Driscoll; D O'Reilly, S Collins, M Moore, T Beirne, W Earle, C Ross, C O'Donnell, R Boucher. Rolling Reps: T Sexton, R Liddington, M Feeley, M Walsh, W Walsh.
OLD BELVEDERE – D Riordan; J Glynn, J Kennedy, B Woods, A Wynee; S Crosbie, A Sheehan; P O'Regan, M Cooney, D Lavery, B Marshall, J Eden-Whatiri, J Slattery, K O'Gorman, L Auva'a. Rolling Reps: K O'Neill, V Soden, C Mallon, F Lawlor, E Devitt.
REF – L Colgan (IRFU).