Johnson came off the bench to replace Alfie Doughty in the 83rd minute, helping the Hatters see out the 2-1 victory with five minutes of added time thrown in.
The 17-year-old was the first academy graduate to play for the first team since James Justin in 2019, and asked how he had been since, Edwards replied: “He’s been great. We’ve had a couple of days off, so seeing him in today, he was just his normal self.
“He came in, has gone about his business and trained really well, as he does every day. We are really pleased for him.
“It was good for the Academy, good for belief for the staff and for his mates to see that there are opportunities and that none of us are afraid to bring people on in big games.
“OK, we can say that in terms of the league position, we’re not going to get promoted in second place. We know we’re in the play-offs, but it was a big game the other night.
“We trust him to go on and he really delivered. He did well and I’m really pleased for him. The hard work really starts now because he’s got to try to stick in and around it.”
Towards the other end of the age range in the squad, Edwards also had praise for his captain Sonny Bradley after a third successive 90 minutes for the 31-year-old.
“This game was the biggest test, no disrespect to the previous two games, but Middlesbrough are a different animal, and everyone would have seen that to the previous two games,” said Edwards.
“He was really tested, in behind, having to cover certain distances at a higher speed than he would have done the other games as well, because Middlesbrough shift the ball so quick and the spaces that they pick up, they overload certain areas and we can be aggressive and try and press and then they’ll go bang and hit you in behind as well.
“They’ve got a lot of ways that they can hurt you, so it was a lot different for him and I thought he defended the box very well on a number of occasions, making first contacts, some good clearances.
“He’s a leader and when we’ve really needed him, and we have, we’ve lost three defenders, he’s stepped in and delivered some really good performances.”
