Ceisiau Paul Diggin, Calum Clark a Stephen Myler sicrhaodd y fuddugoliaeth i'r Saints, enillodd y gystadleuaeth y tymor diwethaf.
Ond fe fethodd y tîm cartref i hawlio pedwaredd cais fyddai wedi sicrhau pwynt bonws.
Treuliodd Dan Wray, Lloyd Burns a Nigel Hall gyfnodau yn y gell gosb i'r ymwelwyr gyda gôl gosb Matthew Jones eu hunig bwyntiau o'r noson.
Northampton: Shane Geraghty; Joe Ansbro, Jon Clarke, James Downey, Paul Diggin; Stephen Myler, Ryan Powell; Soane Tonga'uiha, Brett Sharman, Brian Mujati, Mark Sorenson, Christian Day, Calum Clark, Phil Dowson (capt), Mark Easter.
Eilyddion: Andy Long, Alex Waller, Tom Mercey, Dan Sanderson, Tom Wood, Stuart Commins, Joe Ford, Jamie Elliott.
Dreigiau: Pat Leach; Tom Cheeseman, Tom Riley, Rhodri Gomer-Davies, Aled Brew; Matthew Jones, James Leadbeater; Hugh Gustafson, Steve Jones (capt), Dan Way, Adam Jones, Rob Sidoli, Hugo Ellis, Lewis Evans, Toby Faletau.
Eilyddion: Lloyd Burns, Nigel Hall, Pat Palmer, Luke Charteris, Jevon Groves, Wayne Evans, Jason Tovey, Ashley Smith.
