The 19-year-old hit another milestone in his career on Wednesday evening by earning a first Champions League start in the 6-3 victory away at LASK.
That occasion in Austria was the midfielder's 26th competitive appearance for the club, having made his senior debut back in February 2024.
"Trey is a player that I think, being very young with not a lot of minutes in the first team, he's very mature," Iraola told reporters. "He understands the situations very well, he understands the game very well. Tactically, I think he's really smart.
"But he has to continue doing the steps in the right direction. I'm confident with him.
"He has been involved, I think, in most of the last games, but he has to keep this level of performance, of training.
"If he has to play as a six, as an eight, he has to play one minute, he doesn't have to play, he has to start and play all the game like yesterday – he has to be there, putting pressure also on the other midfielders.
"And I think it's very good for us that we can put \[in\] these young players with not a lot of experience and they can perform in a competition like the Champions League or in the Premier League."
Andoni Iraola's pre-Brentford press conference