Olympic champion Daniel Wiffen doubled up by winning gold in the men's 400m freestyle final on day three of the Irish Open Swimming Championships at the Sport Ireland National Aquatic Centre (NAC) in Dublin.
Wiffen, who has professed his desire to have a crack at the 1500 metre freestyle world record on Wednesday, won the 400m event in three minutes 46.87 seconds from National Centre Limerick's Cormac Rynn - the only other swimmer to go under four minutes.
"I’m adding the 400 this year to my programme and that time was ok," said Wiffen, who also won the 800m freestyle on Sunday.
"I’m only really back in training since January so maybe my expectations for this meet were a little high but I’m confident I can go well in the 1500 (the heats of which are on Tuesday morning)."
"Judging by what's happened over the rest of the week here, I'm not really sure how it's going to go, but I'm optimistic and I want to keep my streak of registering a personal best every time I swim at a major meet."
Earlier 18-year-old John Shortt broke his own Irish senior record in the semi-finals of the 200m backstroke; his time of 1:56.61 was over a second under the old record and is the sixth fastest time in the world this year.
The Galway swimmer, who has also now qualified for this summer's World Championships, will have another opportunity to go even faster in Tuesday's final.
Paris Olympics bronze medallist Mona McSharry had a brilliant 100m breaststroke final against Limerick's Ellie McCartney, who matched the Tennessee-based McSharry pretty much stroke for stroke over the two lengths.
McSharry just held off the 20-year-old McCartney to win by one tenth of a second in 1.06.87, good enough to qualify for the Worlds in Singapore in July.
Ellen Walshe, swimming the 100m butterfly, secured a third qualification time for the worlds, clocking 58.14secs in the heats to take the top seed for the semi-finals where she topped the qualifiers for Tuesdays final in 58.24secs.
Walshe had already secured qualification for Singapore in both the 200m individual medley and 200m butterfly on Saturday.
Elsewhere, Grace Davidson of Ards held off Paris Olympian Victoria Catterson, to win the women's blue riband event, the 100 metres freestyle gold, in 56.05secs, while Eoin Corby from Limerick won the men's 100m breaststroke title 1:01.45secs.
