The Sligo flyweight defeated home favourite Patrick Cappi in Roseto to ensure a second European medal in two years having won Junior silver in 2017.
Clancy claimed a 4-1 split to guarantee bronze as well as book himself a place at the World Championships in Hungary this Summer.
The Ballinacarrow teen took round one on four cards and swayed three judges with him to lead 20-18 on three cards going into the final frame where he picked his shots in the face of a relentless opponent.
Sadly, there was last-eight disappointment for Aoibhe Carabine and Edward Barrett, while Caitlin Fryers, Mary Geraghty and Aoibhe Ginty went out at the last 16 stage.
Barrett lost out to Karol Itauma in an all-southpaw battle but stands a good chance of being one of the seven European fighters at the weight that will head to the World Championships.
Fryers, a World and European Youth medalist last year had a nightmare draw, being pitted against Russian Liubov Sharapova and was edged on a 4-1 split.
A late addition to the squad, Mayo’s Carrabine looked to be on-course for a medal, leading 4-1 at the end of the first but Turk Sagit Emanur battled back to take the final two stanzas.
Ginty and Geraghty lost to German and Turkish opponents respectively
There are six Irish fighters in quarter-final action today looking to join Clancy on the medals podium.
Irish female captain Lauren Kelly will be aiming to secure a second European Youth bronze while World Junior champion Daina Moorhouse is targetting a podium finish in the older age group. European Schoolboys silver medalist Brandon McCarthy will be looking for a second medal in his fifth European Championships while Jude Gallagher and Evelyn Igharo will be hoping to finally make the breakthrough following many near misses. Finally, Leitrim newcomer Dearbhla Rooney is also just one win away from a debut international medal.
48kg Daina Moorehouse (Ireland) v Marta Lope (Spain)
49kg Jude Gallagher (Ireland) v Seyran Yeghikyan (Armenia)
56kg Brandon McCarthy (Ireland) v Muhamet Qamili (Albania)
57kg Dearbhla Rooney (Ireland) v Nikolina Cacic (Croatia)
64kg Evelyn Igharo (Ireland) v Anita Zilic (Croatia)
75kg Lauren Kelly (Ireland) v Sena Erdogen (Turkey)