Conor Ferguson became the first Irish junior to break the two-minute barrier for the 200m backstroke on the first night of the Irish Short Course Championships in Lisburn.
The Larne swimmer cut 1.36 seconds off his own Irish junior record as he clocked 1:59.19 which was also a new Ulster senior record.
Bethany Carson won the 100m freestyle and 200m individual medley titles.
Lisburn swimmer Carson set a personal best of 2:14.50 in the medley event.
Dublin-based Carson's performances indicated that she has now recovered from the ankle fracture which effectively ended her hopes of competing at last year's Commonwealth Games.
Carson was followed home by Paralympic star Bethany Firth in the 100m freestyle with Firth also taking third in the 200m individual medley.
Bangor's Jamie Graham won the 50m freestyle in 22.89 and then went on to clinch the 50m breaststroke gold in 28.13.
Other impressive performances included Antoinette Neamt's 800m freestyle gold.
The 13-year-old Tallaght swimmer's 800m winning time of 8:35.68 was only .44 of a second off Grainne Murphy's Irish junior record from 2009.
Competition continues on Saturday and Sunday.