Bjorn Ludick and Mary Lafferty came out on top at the Lough Neagh Triathlon held at Ballyronan Marina.
A superb cycle by Ludick, originally from South Africa, set up his first victory at Lough Neagh.
Lafferty, of the Setanta Club in Co Louth, had a tougher battle to retain her female title, only taking over the lead on the run.
Conditions were perfect when the athletes entered the chilly waters of Lough Neagh. Ludick was first to complete the 1,500m swim, with a slight lead over Dublin brothers Neil and Colin Bolger.
More than a minute later came many times Irish champion Brian Campbell of organising club Hi Elbow, a previous winner of this race. Of the women, Emma Bamford from Olympian Belfast led out of the water, followed by Joanne Doran of North West.
On the four-lap 40km cycle, Ludick soon powered out of sight.
With a good bike leg, Bamford remained in the lead coming into transition. Behind her, Lafferty, with the fastest bike leg of the day, had blazed through the women's field into second place, with the veteran Anne Paul a close third.
Although Ludick had started the 10km run with a three-minute lead, Campbell was catching up fast. Wayne Reid from Athlone was also making steady progress and moved into third place. With noted runners Paul Curran and Peter Savage also running well, the gaps were closing, but Ludick held on to cross the line in 1 hour 27 minutes 4 seconds. Just 16 seconds behind was Campbell with a run time of 33 mins 36 secs. Reid finished a comfortable third ahead of veteran Paul Carroll.
A strong run meant Lafferty stayed in control of the women's race, finishing in 2 hrs 17 mins 49 secs. Anne Paul was just over a minute behind for second. For third place, Kelly-Anne Speight from Dundee University passed the tiring Bamford, as did fourth-placed Anne O'Leary.
At the other end of the country, a crash at the Suir Valley 3-Day ended the season of Limerick's Colm Turner, who suffered a broken collarbone and elbow. Meanwhile, Trevor Conroy and Kevin Shelly got identical times of 1 hr 1 min 39 seconds to share victory in the Bunclody Sprint Triathlon. The first woman home was Nenagh's Ailbhe Carroll.