Champion Bumper entrant Jezki (even-money favourite) led home previously unraced stablemate The Big Easy in the concluding Killiney (Pro/Am) INH Flat Race at Leopardstown.
Jessica Harrington's four-year-old was carrying a penalty having scored on his debut over the same course and distance in January, but he shrugged off the extra weight with a convincing two-length victory under Mark Fahey.
Jezki was cut to 14-1 from 20s by Stan James, and left unchanged at 16-1 by Paddy Power, for the Weatherbys Champion Bumper at the Festival.
Harrington said: "I'm delighted with both horses. I didn't really want to run them against each other but I had no real option.
"Jezki is a possible for Cheltenham now as I don't think he did any more than a gallop there. He learned a bit more and I think a faster pace will suit him better."