Detroit Lions defensive coordinator Aaron Glenn was facing strong criticism just two weeks ago. But now that the Lions defense has rebounded in a big way, Glenn says his focus is on coaching, not proving the doubters wrong.

After the Detroit Lions lost to the Seattle Seahawks 37-31 in Week 2, fans and some local writers expressed their frustrations with defensive coordinator Aaron Glenn. It wasn’t just about allowing 37 points and nearly 400 yards of offense, but in Year 3 of Glenn’s defense, it was hard to point to any progress that had been made on that side of the ball.

That conversation was shut down quickly.

The next week, Detroit held the Falcons to six points and 183 yards of offense, and on Thursday night, the Packers managed just 20 points and 230 yards of offense—including only 20 yards of offense in the first half.

But if you think Glenn got any satisfaction proving some of his doubters wrong, you don’t know Aaron Glenn. On Thursday, the Lions defensive coordinator reminded the media that he’s been in this business for years as a player and a coach, and to survive, you have to treat all of those reactions as “white noise.”

“I’ve played one of the hardest positions there is in this league and once you get beat, you’re the worst thing there is,” Glenn said. “Once you give up yards, or whatever, as a coach, you’re the worst thing there is and it’s just part of it. Listen, we’re in a business of criticism and that’s not going to change and I know that and that’s just part of it.”

It also helps to have a supportive head coach. Dan Campbell has never wavered in his support of Glenn, because both know the value of patience in this business—which can be rare in a “what have you done for me lately” business.

“I’ve seen a lot of really, really good coaches not have success early and they’re fired, or whatnot,” Glenn said. “And then they end up going somewhere where they have the time to get exactly how they want to be and get the staff they want to get in, get the players they want to get in and you see success happens.”

As recent as last year, the Lions had the youngest defensive roster in football. So it makes sense for the Lions’ defense to have gone through a lot of growing pains over the past two seasons. But this season it certainly appears they’ve taken a jump. They rank 13th in points allowed, fourth in points allowed, fifth in DVOA, and eighth in team expected points added per play.

It’s early, but Glenn is damn proud of the way his team is currently playing.

“Am I happy? Absolutely,” Glenn said. “I mean guys are playing hard. We’re doing some pretty good things, and there’s room for improvement. I’m happy the way those guys are playing.”