The Galway middleweight won his last 16 bout in Vladikavkaz to reach to quarter-final stage for the second year in succession.
Following an impressive Round of 32 win on Saturday, Dossen followed this up with a unanimous decision triumph over Romanian Alberto Simion this afternoon.
Southpaw Dossen landed well early with jabs and lead lefts against a static, slugging foe.
Boxing within himself, the Olympic BC fighter was staying largely out of range through the second, showing some impressive handspeed to constantly pierce the Simion guard from afar.
Countering at will while Simion surged forward in vain in the third, Dossen rounded off the fight at a counter.
Going to the cards in absolutely no doubt, Dossen was confirmed a unanimous decision winner with scorelines of 30-27, 30-26, and a trio of 30-25s.
The dominant result ended a run of four straight defeats for Irish boxers at the championships.
Earlier this afternoon Limerick welterweight Paddy Donovan was eliminated by Russian Vakhid Abbasov which came after a trio of losses on Sunday.
Dossen will now face Russian home favourite Aleksei Semykin in the quarter-finals on Wednesday. There is an Irish link here, with the Moscow middleweight having been beaten by Michael Nevin in the European Junior final back in 2014.
Still just 19, Dossen reached the quarters in last year’s tournament where he was edged out by Georgian Giorgi Kharabadze.
Four other Irish boxers remain at the championships and are just one win from medalling – with Amy Broadhurst, Aoife O’Rourke, and Niamh Earley boxing tomorrow and Adam Hession in action on Wednesday.
Friday March 8th
60kg Amy Broadhurst (Ireland) beat En Gizem (Turkey) 5-0
64kg Shauna O’Callaghan (Ireland) lost to Chelsey Heijnen (Netherlands) RSC2
Saturday March 9th
60kg David Oliver Joyce (Ireland) beat Oleg Chulkyacheyev (Ukraine) 5-0
69kg Paddy Donovan (Ireland) beat Sam Wagensvela (Netherlands) 4-1
75kg Gabriel Dossen (Ireland) beat Andrei Vreme (Moldova) 5-0
Sunday March 10th
57kg Mary Geraghty (Ireland) lost to Victoria Glover (Scotland) 0-5
60kg David Oliver Joyce (Ireland) lost Beslan Khamzaev (Russia) 1-4
64kg Pierce O’Leary (Ireland) lost to Mike McDonagh (Wales) 0-5
Monday March 11th
69kg Paddy Donovan (Ireland) lost to Vakhid Abbasov (Russia) 0-5
75kg Gabriel Dossen (Ireland) beat Alberto Simion (Romania) 5-0
Tuesday March 12th
51kg Niamh Earley (Ireland) v Giovanna Marchese (Italy)
60kg Amy Broadhurst (Ireland) v Kinga Mezovari (Hungary)
75kg Aoife O’Rourke (Ireland) v Anastasiya Shamonovan (Russia)
Wednesday March 13th
52kg Adam Hession (Ireland) v Rotyslav Bilototskyi (Ukraine)
75kg Gabriel Dossen (Ireland) v Aleksei Semykin (Russia)
48kg No entrant
51kg Niamh Earley (Ryston)
52kg Adam Hession (Monivea)
54kg No entrant
56kg No entrant
57kg Mary Geraghty (St Anthony’s)
60kg Amy Broadhurst (Dealgan)
60kg Davey Oliver Joyce (Ballymun)
64kg Shauna O’Callaghan (Clann Naofa)
64kg Pierce O’Leary (Dublin Docklands)
69kg No entrant
69kg Patrick Donovan (OLOL)
75kg Aoife O’Rourke (Castlerea) C
75kg Gabriel Dossen (Olympic) C
81kg No entrant
81kg No entrant
+81kg No entrant
91kg No entrant
+91kg No entrant
Team Manager: Stephen Molloy
Head Coach: Dmitry Dmitruk
Coaches: Anita Just, Philip Keogh