Michael Conlan says a slap on the head from coach Billy Walsh drove him on to pull away in the final round and beat Frenchman Nordine Oubaali to guarantee a third Olympic boxing medal for Ireland.
The 20-year-old Belfast man struggled to assert himself early against his stockier, more powerful foe, but turned up the heat after heading into the final round level to claim a 22-18 victory.
Conlan, who joins team-mates John Joe Nevin and Katie Taylor in their respective semi-finals with Paddy Barnes still to come, said: "My coach told me to put the boot in because I was a bit too quiet. Thank God he gave me a slap on the head and drove me on.
"Words can't describe what I'm feeling but I knew I'd be here on the day. When I watched Andy Lee and Amir Khan in 2004 I told my mother I would be here. Hopefully I can go one better than Khan and go all the way."
The compact Oubaali produced the cleaner work up front in the first round, but Conlan ended the round well to chisel a 5-5 tie. They were level again at the end of the second, Oubaali's intensity keeping him on a par with the more adventurous Irishman.
But Conlan stepped it up in the third, stabbing home a fine left hand as the Frenchman's work lost its snap. A grandstand finish from the Belfast man, in which he landed with both left and right hooks, helped him pull it out in style.
Conlan will face Robeisy Ramirez Carrazana, in the semi-finals while the second semi will see brilliant Russian world champion Misha Aloian take on Tugstsogt Nyambayar of Mongolia.
Aloian produced a superb performance of amateur boxing skills to see off teenage Puerto Rican Jeyvier Cintron 23-13, while the rugged Mongolian came on strong in the last round to defeat Uzbek Jasurbek Latipov.