Dossen, still just 16 years old, claimed bronze in St Petersburg in what was his first major international tournament.
The Galway boxer only joined Mongan’s club last year, moving from Furbo Boxing Club in Spiddal, and Mongan admits that he is astounded with the light welterweight’s progression.
The young coach spoke to Irish-Boxing.com and described how “Gabriel only came to us in March 2015 and we put him straight into the Senior Cadet Championship and he was beaten in that, then beaten in another one, but the progress in one year has been phenomenal.”
“He’s worked on his faults and he’s turned it around. He went on to win the Connacht Championships, the National Championships, the Haringey Box Cup, the Under-18s.”
“On paper he was an international novice and he went out in his third international bout and wins a World Youth bronze medal.”
“I couldn’t ask any more from him.”
Dossen’s Olympic team-mate Frankie Cleary, who won the Senior (Intermediate) lightweight title on Friday, added that “Gabriel is a great lad. We knew through the last few months that he was improving all the time. He went in as an underdog and he proved everybody wrong.”
“He should be very proud of himself, because we’re all very proud of him back home.”