Darren Donnelly struck a hat-trick of goals during this emphatic preliminary-round victory over a youthful St Mary's at Mountbellew.
Favourites Roscommon CBS were always in control, once Mark Healy bundled home a 10th-minute goal.
Donnelly bagged a second three-pointer in the 17th minute as St Mary's were unable to deal with their opponents' pace and power.
In the 23rd minute, Healy netted another and Donnelly converted a penalty on the stroke of half-time as Roscommon went in 4-4 to 0-4 ahead at the break. After the restart, it was a similar story, with Donnelly adding his third goal in the 42nd minute.
Scorers -- Roscommon CBS: D Donnelly 3-1 (1-0 pen), M Healy 2-0, C Casey, H Walsh, E Lannon (1f) 0-2 each, M Nally, P Kenny (1f) 0-1. St Mary's, Galway: C O'Laoi 0-5 (4f), S O'Flatharta (0-1).
Roscommon CBS -- M Whyte; P Neilan, M McNeill, K Kilcline; O Hannon, C Shaw, C Casey; M Nally, K Kilcline; R Earley, M Healy, B Fannon; P Kenny, E Lannon, D Donnelly. Subs: H Walsh for Healy (45), C Clarke for P Kenny (45), E Keenan for Hannon (50), D Gibbons for Neilan (58), K Farrell for Fannon (58).
St Mary's, Galway -- J McMahon; D Duffy, D Kerr, C O'Toole; R Cusack, J Wynne, P Gibbons; A McGinty, C Delampard; R Lavelle, C O'Laoi, P Fahey; S O'Flatharta, P Healy, C Tansey. Subs: C Noone for Kerr (31), T O'Malley for Healy (50).
REF -- L Lohan.