Ireland's Ciaran O'Lionaird produced a composed performance to qualify for the 1500 metres semi-finals at the World Championships in Daegu.
Championship debutant O'Lionaird kicked impressively in the closing stages to secure automatic qualification by placing sixth in his heat in 3:40.41.
The Corkman made a massive breakthrough earlier this month when he clocked 3:34.46 at a meeting in Belgium.
That secured his place at both the World Championships and London 2012.
O'Lionaird, 23, showed real racing maturity in Tuesday's heats as he finished ahead of Spain's former European Indoor Champion Juan Carlos Higuero and US hopeful Leonel Manzano.
Those ahead of O'Lionaird were all world-class Africans including defending champion and Kenyan native Yusuf Saad Kamel who represents Bahrain.
The heat was won by Morocoo's Amine Laalou in 3:3.86 ahead of Ethiopia's two-times World Indoor champion Deresse Mekonnen (3:40.08), Kenya's Silas Kiplagat (3:40.13), Algeria's Taoufik Makhloufi (3:40.15) and Yusuf Saad Kamel (3:40.27).
O'Lionaird will now be involved in the semi-finals on Thursday (1155 BST).
Irish medal hope Olive Loughnane will be in action in Wednesday's only event at the Championships.
Loughnane competes in the 20K walk where she won silver in Berlin two years ago.
Russia's defending champion Olga Kaniskina will go in as favourite with compatriots Vera Sokolov and Anisya Kirdyapkina being tipped to be her main challengers.
Sokolov and Kirdyapkina posted the world's two fastest times in history having clocked 1:25:08 and 1:25:09 in the Russian Winter Championships in Sochi in February.
However, Kaniskina has produced consistent form this summer and goes into the event as favourite.