Katie Kirk ran the race of her life in yesterday's AAA's Under-20 Championships in Bedford when she destroyed the field to take 400m victory in a new NI Junior record of 53.69 seconds.
This performance by the Lagan Valley athlete sliced a huge 1.3 seconds off her PB and ensures her selection for the GB team to compete in the European Junior Championships in three weeks.
North Down's Ben Reynolds was second in the high hurdles in 14.10 seconds.
The race was won by Commonwealth bronze medallist Lawrence Clarke in 14.01 seconds.
In the equivalent Irish Championships at Tullamore, Ballymena's Joanna Mills also sliced a massive 0.74 seconds off her 400 metres PB to win in 54.02 seconds.
Team-mate Dean Adams followed up his NI Senior 100 metres win to take the Irish Under-23 title in a time of 9.98 seconds, which was assisted by a four metres plus wind.
A high quality Men's Hammer lived up to expectations with victory going to Killian Barry of Crusaders with an Irish Junior record throw of 68.38 metres.
Finn Valley's Dempsey McGuigan also had a fine throw of 66.71 metres for second which was marginally short of his PB.
Andrew Doyle of Mid Ulster was fourth with 62.64 metres.
All three athletes are qualified to compete in Tallin.
Lisburn AC's Ciara Mageean did not compete in the 1500 metres because of a swollen ankle which required a cortisone injection.
While coach Eamon Christie does not consider the problem serious, Ciara must race again prior to the Junior European Championships to prove her fitness.
In Ciara's absence the race was won by Banbridge's Emma Mitchell.
Meanwhile, Kerry Harty of Newcastle continued her good form when she outsprinted GB internationals Charlotte Best and Faye Fullerton to take victory in the Sunderland Elite Road Mile in 4 mins 44 seconds.
In the North of England Championships in Manchester, Strabane's Aaron Crawford finished fourth in the javelin when he added 1.5 metres to his PB with a throw of 65.40 metres.