Leinster 'A's quest for a third consecutive crown came to an end at Sixways Stadium last night as they succumbed to a narrow defeat.
There was little to separate the teams for the majority of a tension-filled contest, but tries in either half by Mat Gilbert and Percy Humphreys edged it for the English Championship outfit.
With 58 points apiece, Leinster's Cathal Marsh and Tiff Eden of Worcester are scorers-in-chief for their respective sides, but neither fly-half was able to break the deadlock early on.
Home winger Tom Biggs was held up just shy of the line 16 minutes in, and after holding firm in defence, the champions gained the ascendancy thanks to Marsh's routine 28th-minute place-kick.
However, when Peter Dooley was sin-binned towards the end of the half, Worcester took advantage with a well-worked converted try from Gilbert.
A second Marsh penalty reduced the gap to 7-6 at the break, but upon the resumption, the visitors were struggling for territory.
The Blues backline (which included first-team regular Ben Te'o) were making a fleeting impression, but after superbly a collecting a high ball, full-back Humphreys crossed over for a crucial unconverted try 12 minutes from the end.
The Worcester line was finally breached by the industrious Noel Reid in stoppage-time, but even though Marsh added the bonuses, an earlier three-pointer from Alex Symons had effectively sealed their fate.
Worcester Warriors - P Humphreys; S Smith, A Grove, R Fatiaki, T Biggs; T Eden, JB Bruzulier; O Fainga'anuku, B Sowrey, J Rees; J Percival, D Sanderson; M Cox, M Gilbert, R de Carpentier. Reps: D George, R Bower, M Daniels, H Taylor, J Arr, A Symons, D Hammond.
Leinster 'A' - C Kelleher; S Coghlan-Murray, B Te'o, N Reid, M McGrath; C Marsh, L McGrath; P Dooley, A Dundon, R Burke-Flynn; R Molony, T Denton; B Marshall, D Leavy, P Timmins. Reps: B Byrne, I Hirst, T Beirne, J Coghlan, C Rock, S Crosbie, C O'Shea.