LOUISVILLE, Ky. -- When Louisville Cardinals coach Bobby Petrino walked into his postgame news conference after a triumphant 31-13 season opener against the Miami Hurricanes, the first question he got was not about his new quarterback or workhorse running back.

Nope. The defense wrote the signature on this victory.

So Petrino was asked about his defense first, and then his defense a little bit more, and each time he heaped more praise on a group that faced a series of questions heading into the game Monday night.

With a new scheme, a new coordinator and seven new starters, the Cards did not stand a chance to match their group from last year, did they?

They did.

Louisville absolutely dominated Miami in a rematch of their bowl game from last postseason, and it was a near carbon copy of the results from that December contest. Louisville's defense was a new, reinvented version of itself under first-year coordinator Todd Grantham. The Cardinals looked faster, but they were still physically dominant, pushing around a veteran Miami offensive line while holding running back Duke Johnson down and flummoxing freshman quarterback Brad Kaaya.

In its last two meetings with Louisville, Miami has scored a combined 22 points, gained a total of 418 yards, and converted just 1-of-24 third-down opportunities.

With a stifling defense, Louisville took the burden off new starting quarterback Will Gardner and placed its offense in the hands of running back Dominique Brown, who had an eye-popping 33 carries for 143 yards and a score. The two units worked in concert with each other, but the defense stood tallest considering all the uncertainty going in.

"Our defensive staff had a great plan going in and really worked hard at it," Petrino said. "That's the thing that I really noticed, how fast our defense played. We tackled well and we got a lot of guys to the ball."

Having a healthy Johnson gave the Canes hope they would reverse their dismal performance from last postseason. But he was essentially a nonfactor, despite rushing for 90 yards on 20 carries. Take away his long run of 24 yards and he averaged just 3.5 yards per carry -- well off his career average of 6.6 yards.

The key, simply, was to cut off the edge.

"When he did get to the edge, we had some problems in the middle of the defense, but a couple of the guys were saying that we're quicker now, so now we're able to keep up with backs like that, so basically keeping him contained from the outside was a big deal," Louisville linebacker Lorenzo Mauldin said.

The quickness was evident. Having four fast linebackers on the field was a big reason why. Not only was Mauldin doing his best to get into the backfield from his new outside linebacker position, but Deiontrez Mount was making his presence felt with a sack and two tackles for loss. So was linebacker Keith Kelsey, who had a fumble recovery and five tackles.

Then there was safety James Sample, the former Washington Huskies player who transferred from junior college and got the start. Louisville lost plenty of experience and production from safeties Hakeem Smith and Calvin Pryor, so filling that spot was the biggest concern heading into the season.

But Sample played better than anybody anticipated, leading the team with eight tackles and a crucial interception in the third quarter with Louisville up 21-13. The Cards scored a field goal on the next possession to put the game out of reach.

For Mauldin, the only recognizable player left on the defense from 2013, the result had to be particularly satisfying. No defense of his would start taking a step back, regardless of new faces and new scheme.

"As the leader of the defense, you just look at what you've got and you say, 'This is what we've got. This is what we're going to make of it, get the guys that are young, get the guys who are new to go along with the defense,'" Mauldin said. "You can't think negative about anything when it comes to a team, because if you think negative the team feeds off you. What I'm doing is picking the guys up, letting them know that if they miss a play, you've got it the next play. Forget about [that] play and move on. Just positive energy."

Louisville could not have planned a better start to ACC play. And the Cards will only get better from here. The schedule sets up for a 6-0 start headed into the showdown against Clemson, with Syracuse the only bowl team on Louisville's schedule over the next five games.

But looking ahead is for another day. Let the defense have this one.