Arsene Wenger and Thierry Henry were among those to praise Eddie Nketiah after the 18-year-old came off the bench to hit a brace on his home debut for Arsenal.
The England Under-19 international proved the difference as the Gunners came from behind to beat Norwich 2-1 after extra-time and take their place in the Carabao Cup quarter-finals.
Josh Murphy had given the Canaries a surprise lead at the Emirates Stadium but Daniel Farke's side missed a number of chances to seal a famous win before Arsenal hit back.
Wenger, who made 11 changes from the side that won 5-2 at Everton on Sunday, turned to Nketiah with five minutes to go and the former Chelsea youngster responded with an equaliser just 15 seconds after entering the fray.
That sent the tie to extra-time where Nketiah, who had played one minute of senior football before Tuesday's game, headed home Mohamed Elneny's corner to send Arsenal through to the last eight.
"I brought him on because we needed to score goals and he can score goals. In the end we had eight strikers on the pitch," Wenger said.
"I knew he had quality, but when the team need you and you deliver, that's another quality you don't know about until you go on to the pitch.
"Hopefully he'll have a long career at Arsenal. We're proud to give chances to young players, it's part of our DNA, and we want to continue to do that.
"I don't know why exactly Chelsea let him go or if he decided to leave, but young players more and more nowadays travel from one club to another. We're happy to have him.
"I can't remember a young player having such an impact in a game like that. Until he came on we lacked ideas and creativity."
Henry, Arsenal's all-time leading goalscorer and now a Sky Sports pundit, tweeted his congratulations to Nketiah.
"What a night for @EddieNketiah9. So happy for him and not surprised at all!" he wrote.
Norwich travelled to the Emirates Stadium on the back of a 1-0 win over local rivals Ipswich on Sunday.
Farke's side created plenty of second-half chances to add to Murphy's well-taken opener but failed to beat Arsenal debutant Matt Macey.
But Farke pointed to an incident after the interval where Elneny escaped a red card after he hauled down Nelson Oliveira as the Portugal international burst through on goal as a key point in the contest.
"I'm not a guy who calls for red cards, but this situation because we were one on one with the goalkeeper. That's almost 100 per cent 2-0 and then we're in the next round," Farke said.
"Elneny should have seen a red card and then it's 11 men against 10 and they are not able to build so much pressure and there are not all those set pieces and no 1-1. To accept this decision is really hard."