FIRST-half goals from Jack McCarron and Donal Smyth set DCU up for a clear-cut win in this mediocre O'Byrne Cup tie at wintry Dr Cullen Park.
Although Eoghan Ruth put Carlow in front, DCU quickly found their stride, their swift inter-passing and movement creating major problems.
McCarron struck in the 11th minute to put his side into a 1-1 to 0-2 lead – an advantage they never lost. The Carlow defence was breached again in the 25th minute when Donal Smyth smashed home a superb goal.
By half-time, the visitors held a 2-4 to 0-3 lead, and the second half saw no improvement in Anthony Rainbow's side.
The third DCU goal killed any hope of a Carlow revival, with substitute Conor McGreanor steaming through the heart of the home defence before crashing the ball to the net in the 55th minute.
Carlow, who scored a morale-boosting win over Wicklow in mid-week, tried hard but lacked cutting edge. By comparison, the DCU attack was very impressive, particularly double Dublin All Star Paul Flynn and McCarron.
Without star midfielder Brendan Murphy, Carlow struggled badly.
The focus of manager Rainbow will now switch to the league as he seeks to plot a path out of Division 4.
McCarron top-scored with 1-3 as DCU recorded their first win in the competition, having drawn against Wicklow and lost by 11 points to group winners Dublin.
Scorers – DCU: J McCarron 1-3 (0-2f), C McGreanor 1-1, P Flynn 0-3, D Smyth 1-0, B Donnelly 0-1. Carlow: W Minchin, D Foley (2f) 0-3 each, E Ruth 0-2.
DCU – J Farrelly; J Smith, J Cooper, C Ellis; J Brady, E Doherty, M Quinn; C Dunleavy, P O'Hanlon; S Carey, P Flynn, C Diamond; J McCarron, B Donnelly, D Smyth. Subs: F Cregg for Smyth (47), J Quinn for O'Hanlon (47), C McGreanor for Flynn (51), L Bree for Cooper (53), S Carty for Carey (61). Carlow – C Kearney; K Byrne, S Mernagh, T Bolger; K Nolan, D Hayden, M Doyle, D Foley, S Redmond; C Moran, P Reid, E Ruth; K Hession, W Minchin, D St Ledger. Subs: B Kavanagh for Bolger (42), T Bolger for Nolan (52), A Kelly for St Ledger (64), BJ Molloy for Hayden (64).
REF – S Johnson (Meath)