Manchester United's under-19 side beat Sabah FK 5-0 at Leigh Sports Village in their opening UEFA Youth League match, a competition that mirrors the Champions League by pitting academy sides against the same opponents the first team faces in Europe. Gabriel, 15, scored a hat-trick, with Amir Ibragimov and Jacob Watson also on the scoresheet in a dominant display.
The teenager already trains regularly with United's first team and is increasingly expected to be handed his senior debut at some point this season. Under-21 boss Adam Lawrence praised his development after the win.
"He's obviously a talented lad," Lawrence said. "And he's in a great place at the moment and really enjoying his football. And I think you could see that in his performance today. Naturally, it was a game where we had a lot of the ball.
"The keeper made a couple of good saves from a couple of his shots, a couple that didn't quite come off. But you always feel that he's a threat in and around the box and then nice for him to get the couple late on to get the hat-trick as well.
"So yeah, that type of performance has been him in the first part of the season."
Asked how to coach a player with Gabriel's natural flair, Lawrence said the priority was to protect his instincts rather than restrict them.
"Well, I think the first thing in my job is not to ruin him," he said. "So when you have a talented player like JJ and the other lads of course, you obviously don't want to stifle their freedom and their creativity. And I think essentially what you try and do is to set the team up to allow the talent to function and to play free at the right moments.
"Of course, it can't always be free and off the cuff in terms of some of the off-the-ball responsibilities that he's working on and some of the pressing things that he's thinking about. But again, in terms of how he plays properly and how he connects with other teammates at the top end of the pitch, he's just in a real good space."
Lawrence also pointed to Gabriel's grounded personality as a key factor in his rapid development at Carrington.
"JJ is surrounded by people that really believe in him," he said. "From the top of the club right the way through. Where he's been at the club for so long, he's got good relationships with the players, with the staff. Over the course of time that helps as well."
Gabriel has now contributed five goals and two assists in three appearances across all competitions this season.