Waterford's hurling boss was content with his team's performance in their league opener yesterday.
0.21 to 2.15 the full-time score in the capital with Stephen Bennett shooting 2.10, DJ Foran hit 3 points, with Austin Gleeson and Colin Duford chipping in with singles.
Bennett's two goals came by way of well-taken penalties - with black cards issued prior to each.
In all, the referee had to offer 2 black, 13 yellow, and 2 red cards on the day - with Waterford captain Conor Prunty receiving one of the reds late in the game.
Cahill said the result was more positive than negative.