The first came on 17 minutes following a sweeping movement out of midfield, edging the home sidei nto a 1-2 to 0-2 lead.
Eanna O’Connor points kept the visitors in touch but a second Brosnan goal after 23 minutes helped his side to a 2-4 to 0-4 interval lead.
DCU opened the second half impressively with two quickfire points from Ryan Burns and Shekroz Akoram. But Brosnan steadied Wexford with two pointed frees, setting up a final round clash with Dublin on Sunday.
B Brosnan (2-4, 4 frees); J Stafford, P Curtis (0-1 each).
E O’Connor (0-4, 1 free); R Burns (0-2, 1 free); M Plunkett, J Mealif, S O’Brien (f), S Akoram (0-1 each).
P Murphy; R Tierney, J Rossiter, J Wadding; K Butler, J Lacey, T Rossiter; P Byrne, S Byrne; J Firman, B Brosnan, J Stafford; R Nolan, T Byrne, P Curtis. Subs: R Villego for Lacey; S Gaul for Rossiter; R Barronb for T Rossiter; G Carty for T Byrne; I Carty for Brosnan; D Barden for Tierney; P J Banville for Nolan; C Kehoe for S Byrne; K O’Grady for Curtis.
S Mannion; E Smith, C Doran, D Neary; J Mealiff, K Feely, B Crawley; S O’Brien, C McGonagle; C Mulligan, S Carty, T Lahiff; E O’Connor, H McFadden, J Durcan.
S Akoran for Neary; D Mannix for O’Brien; R Burns for Lahiffe; T Galligan for O’Connor; E Smythe for Mulligan; M Plunkett for Durcan.
D Hickey (Carlow).