Mark Johnston had a terrific record at Dundalk last year and the Yorkshire-based handler struck again on the all-weather track when Below Zero won the Bar One Racing Handicap.
Fran Berry made the most of a good draw in stall three on the four-year-old, getting away quickly and grabbing the rail as he led the way in the valuable sprint.
Favourite The Reaper followed him into the straight, but Below Zero (15-2) was not for catching and went clear in the final furlong to score by four lengths.
There was no such luck for Johnston in the feature race, the Irish Stallion Farms EBF August Handicap, as favourite Oceanway dropped away tamely and finished last.
Up front Elusive Ridge led them to the final furlong, where both top-weight Northgate and the always prominent Jackaroo (8-1) swept past and fought out the finish.
Northgate looked about to win, but Jackaroo would not be denied and responded to Joseph O'Brien's urgings to prevail by a head for the Aidan O'Brien team.
Paul Deegan's Moonreach (5-2) dropped back to five furlongs for the first time in nearly two years and found it to his liking as he took the LMFM Race to initiate a double for Fran Berry.
Favourite Calm Bay looked to be travelling nicely entering the final furlong, but Moonreach hauled him in as the line approached before holding Jembatt by half a length.
Johnny Murtagh got Disagree smartly away in the Irish Stallion Farms EBF Auction Maiden and Ger Lyons' youngster (3-1 favourite) got the better of market rival Bogini to win by a length and three-quarters.
The same jockey-trainer combination also landed the Irish Stallion Farms EBF Fillies Maiden as Jemima's Pearl (4-1) led all the way and stayed on stoutly to win by two and a half lengths from Mahaazen
Eddie Lynam's Jolie Jioconde (100-30) ended a string of seconds by winning the Anglo Printers Maiden under Keagan Latham, challenging a furlong out and scoring by two lengths.
