Na Fianna have moved a step closer to a first ever Dublin SHC title success but will have to overcome Cuala in the last four.
Donal Burke's eight-point haul, and 1-4 from fellow Dublin attacker Colin Currie, propelled the Mobhi Road men through to the last four.
Their task was made a little easier by the 54th minute dismissal of St Vincent's top scorer John Hetherton for a second yellow card.
Three points separated the teams at that stage and Na Fianna took advantage of the situation to push five clear with late scores from Currie, Burke and sub Sean Baxter.
The subsequent draw for the last four pitted them against group winners Cuala while holders Kilmacud Crokes will meet Ballyboden St Enda's.
D Burke (0-8, 3 frees, 1 65); C Currie (1-4, 0-3 frees); H Fenlon, S Barrett (0-2); F Breathnach, AJ Murphy, S Baxter (0-1).
J Hetherton (0-5, 2 frees); R McBride, J Mulcahy, M Sweeney (0-2); C McBride, D McBride, O Lanigan, T Connolly (1 free), C Burke, B Bolger (0-1).
J Tracey; S Burke, L Rushe, M Oliver; M Murphy; D Clerkin, C McHugh, H Fenlon; S Currie, P Feeney; T Brennan, D Burke, S Barrett; AJ Murphy, C Currie.
D Ryan for Oliver (30+2); F Breathnach for Brennan (41); S Baxter for Murphy (50); S Ryan for Barrett (53).
D de Poire; E O'Neill, S Gormley, B Moorehouse-Carroll; O Lanigan, C Burke, D McBride; M Sweeney, T Connolly; J Mulcahy, R McBride, B Bolger; A Moore, J Hetherton, C McBride.
N Billings for D McBride (9-10, blood); S Mulcahy for Moore (35); Billings for Gormley (47); S McGarry for C McBride (64).