Steve Bruce was prepared to let Joelinton off the hook after his incredible miss from on the goal-line at Morcambe last night.
But insists that Newcastle United staff members must strive to bring out the poacher in the Brazilian striker.
There was nothing wrong with his two first-half goals at the League Two venue, but Bruce wants more.
Joelinton opted to leave the ball after Jacob Murphy's swirling cross before the Shrimpers cleared the danger.
When asked about his remarkable miss, he said: "I think, after speaking to him at half time, typical Joe, and this is where he might have to be more selfish, he thought it was going in, and he wanted Jacob to have his goal.
“He’s let it go, and thought it was going in the net. That’s his explanation.
“I was delighted when he put one in the top bin and cut in.
"You can see that ability we know he’s got, we’ve just got to bring it out of him."
Bruce also indicated he still sees Joelinton - at 24 - as a player learning his trade.
He said: “Let's not forget he’s only young.
"Jacob Murphy’s older than him.
"He’s still got a bit to do, but it’s not going to do him any harm when he scores a goal like he did today and contributes like we know he can.”