Sycerika McMahon narrowly missed out on qualifying for the London Olympics on the opening day of competition at the Celtic Tri-Nations at the National Aquatic Centre in Dublin.
The two-time European junior gold medallist set a new Irish record in the 100 metres breaststroke, clocking a time of 1:08.79.
The 17-year-old, who has just returned from a US training camp, missed out on Olympic qualification by just three tenths of a second.
Brendan Hyland produced an outstanding swim to win the 200m butterfly in 2:01.87, shaving nine tenths of a second off the Irish record set by former Olympian Colin Lowth in 1999.
Speaking afterwards Hyland said: “I am delighted with my swim, I knew I had it in me but I didn’t think I would be rested enough to go that fast.
“It was a bit of a surprise, I was only going for the junior record, so I was delighted to get the senior record as well.”
Melanie Nocher, the European short course bronze medallist, has come close achieving the required Olympic A standard time in the 200m backstroke which stands at 2.12.78. She takes to the pool in her favoured event on Sunday.
The meet at the NAC is an official Olympic qualifier and Irish swimmers have until the 31 May to register a qualifying time for London 2012. Grainne and Barry Murphy are the only swimmers to have achieved that feat so far.
Elsewhere, Chris Bryan finished eighth at the FINA 15K Open Water Swimming Grand Prix in Cancun, Mexico, on Thursday.
Tri Nations Points Day 1 – Ireland 9,775 points Wales Scotland 8771 points
Men 50m Backstroke Final: 1st K Burdis Ireland 26.08 2nd C McNally Scotland 27.30 3rd J Sloan Bangor SC 27.65
Women 50m Backstroke Final: 1st M Peris Spain 28.29 2nd A Cooney ESB SC 30.00 3rd J Roberts Ireland 30.12 (IJR)
Men 100m Freestyle Final: 1st R Renwick City of Glasgow 51.15 2nd C Coulter Ireland 51.74 3rd A Stirling Scotland 52.21
Women 100m Freestyle Final: 1st H McCarthy Wales 57.29 2nd S Harkin Scotland 57.59 3rd H Miley Scotland 57.97
Men 200m Butterfly Final: 1st B Hyland Tallaght SC 2:01.87(IJR & ISR) 2nd I MacMillen Scotland 2:02.04 3rd T Haffield Wales 2:02.69
Women 200m Butterfly Final: 1st S Oliveira Portugal 2:12.87 2nd A Thomas Wales 2:14.28 3rd S Kelly Ireland 2:18.42
Men 100m Breaststroke Final: 1st J Graham City of Glasgow 1:04.46 2nd N Quinn Ireland 1:05.15 3rd M Dawson Ards SC 1:05.54
Women 100m Breaststroke Final: 1st S McMahon Ireland 1:08.79 (ISR) 2nd S Lougher Wales 1:09.67 3rd K Buchan Scotland 1:11.41
Men 1500m Freestyle Final: 1st T Allen Wales 15:53.09 2nd A Meegan Ireland 15:54.57 3rd M Cremin Scotland 15:57.45
Women 400m IM Final: 1st H Miley Scotland 4:41.28 2nd A Tennant 4:55.64 3rd N O’Sullivan UCD 5:00.01
Men 4x100m Freestyle Team Relay: 1st Scotland 3:29.52 2nd Wales 3:31.73 3rd Ireland 3:35.15
Women 4x200m Freestyle Team Relay: 1st Ireland 8:09.38 2nd Scotland 8:25.76 3rd Wales 8:29.05