Sean McComb marched into the last eight of the European Championships after a sensational defeat of world No 1 Vitaly Dunaytsev.
The Holy Trinity man has easily dealt with Czech Erik Agateljan in his 64kg opener to set up a collision with the reigning world champion.
The classy Russian was expected to be a bridge too far for McComb, but he produced a superb performance in Ukraine to leave himself one fight from bagging a medal. Victory also sealed McComb's place at the Germany World Championships in August.
McComb will meet English fighter Luke McCormack in the quarters after his defeat of Spaniard Johan Orozco Ojeda.
In the evening session, fellow Belfast boxer Brendan Irvine also progressed to the last eight with a unanimous decision over Turkey's Batuhan Citfci.
Fighting in the 52kg category, Irvine started tentatively but began to work his opponent out and showed class and poise to progress in Kharkiv, while also securing his berth at the upcoming Worlds.
Irivine faces Spain's Gabriel Escobar, from Madrid in next round, knowing victory would guarantee a medal at these championships.
Sean McComb beats the World Number 1 to advance to the last 8 at the Europeans and book his place at the World Championships 👊 What a Man 👌 pic.twitter.com/BLxKO8Ut0n— Holy Trinity ABC (@HTBC_Belfast) June 19, 2017
There was no such joy for Irish super-heavyweight Dean Gardiner, who was stopped in the second round of his last-16 bout by Ukrainian Viktor Vykhryst.
Gardiner came out aggressively in the opening three minutes but the home fighter began to assert himself towards the end of the round.
Gardiner was adjudged to have slipped on his first two trips to the canvas, but midway through round two he hit the deck courtesy of a cracking left hook from Vykhryst. Gardiner got to his feet but the Ukrainian was quick to swarm the Tipperary man and force the stoppage.
Hard luck to Dean Breakfast Gardiner the Ukrainian is very good and a big man too. Thought Dean had a decent first round, I gave it to him.— Eric Donovan (@eric_donovan60) June 19, 2017
Flyweight Brendan Irvine is in action later this evening in the last 16 stage of the flyweight division.