"I was absolutely delighted," said Johnson. "It was a fantastic performance, even if we'd have come in at two-all, I'd have been delighted with the players because we were a class above.
"They're big, strong and they're going to get balls into the box. Their front two are dangerous but, on the break, we looked slick, we moved the ball well, we looked dangerous.
"We were rapid on the break. We're getting there now and I was well chuffed with that. Some young players came to The Den, which is a difficult place to play and weren't intimidate and we played our football.
"Thank you to the fans as well because on a Tuesday night to travel this distance and sing their hearts out - I'm delighted we could send them home happy.
"I knew how tough Saturday was because Burton are a tough side to play and we were really tired.
"We had some real energy and pace about us. I can't be prouder of a group of young players tonight."
Goals from Sam Winnall and Alfie Mawson overturned the Lions' lead only for the home side to level late on. Thankfully, Lewin Nyatanga popped up to nod home in the second minute of stoppage time and seal the points.
"I've got to say congratulations to Lewin on his birthday," added Johnson. "He deserves an extra Yorkshire pudding in his post-match meal."
