"I think our effort was probably good," Rasner said after practice Wednesday. "I think what the video showed is that our tackling wasn't very good. So that's what we worked on this week.
"We started every practice this week with fundamental tackling drills. We worked on coming to balance, shooting our hands and moving our feet through the tackle."
Rasner said it was pretty clear that defensive coordinator Paul Haynes thought there were way too many missed tackles in the first game -- that and the 24 points on the scoreboard.
"Obviously, that number was way bigger than what we expected," Rasner said. "I thought there were times where we were in position to make the play, maybe tackle the quarterback for a loss and then we let him escape and make a play.
"There was one play where he escaped from a sack, the receiver fell down and then got back up and made a play. That shouldn't happen.
"But everything that happened can be corrected. We know that was the first game and we have to do better than that and we will."
Haynes said it was probably a typical first game in many respects.
"It's probably never as good as you think and never as bad," he said. "The most disappointing was the drive just before halftime. We talk a lot about drive analysis and you just can't give up 10 yards to start it when they begin at the 36. I was disappointed in that drive in the two minute and then there were three series at the end where they gained 70. That shouldn't happen."
Haynes said all of the things he saw on video "are fixable. There are things that we did all fall camp that we didn't do in the game."
Later, Haynes added, "Our expectations are high. We know we can play better and so we will."
The tackling circuits were a repeat of drills that the defense did on a regular basis early in fall camp.
"We did those early and we needed to do them again," he said. "We emphasized those again yesterday and today."
Haynes said the secondary improved as the game progressed.
"We got better," he said. "Tevin Mitchel got better and Eric Bennett got better. Ross Rasner actually had a good game. He was very productive."
Production is an area that Haynes tries to measure during video evaluation. There are points given for assignments, tackles, interceptions and there are minus points for missed tackles and assignment errors or loafs.
Haynes said the leaders for production were Rasner, along with defensive ends Chris Smith and Deatrich Wise.
"Wise had only six plays, but he was up there with 20 production points," Haynes said.
Some others had plenty more chances, but not near the production. For example, safety Rohan Gaines had 66 snaps in the nickel defense but not a lot of points.
"He can get more production," Haynes said. "But he played good. As his knowledge increases, he's going to do better. I was pleased with Rohan."
Haynes was asked about the decision to bench cornerback Darius Winston in favor of backup Kaelon Kelleybrew early in the game.
"Darius is a senior and we expect a lot from him as far as production," Haynes said. "Maybe we should have gotten him back in the game sooner. But Kelleybrew was doing alright."
Haynes said he's not certain who will start Saturday night between Winston and Kelleybrew.
"We are going to evaluate the whole week," Haynes said. "That spot is up for grabs."
Haynes was asked how much blitz packages were used in the opener. He said the ideal mix is 33 percent zone, 33 percent man and 33 percent pressures.
"Sometimes you think you blitz, then you go back and maybe you didn't get to the pressures as much as you wanted," he said. "That's probably where we were."