Posted by ESPN.com's Tim Griffin

Oklahoma’s defense already had supreme confidence long before the Sooners lost starting quarterback Sam Bradford and were forced to insert redshirt freshman Landry Jones into the starting lineup.

That quarterback switch didn’t prompt an attitude change from the Sooners’ single-minded defensive purpose. It was already there.

	Boyd Ivey/Icon SMI
	Gerald McCoy and the Sooners are looking forward to facing Miami on Saturday.

“Regardless of who is playing quarterback, we’ve wanted to be pretty good as a defense and we know our mindset,” Oklahoma sophomore linebacker Travis Lewis said. “If they can give us a field goal, we think we can win any game.”

That assurance would have been expected to be tested by Bradford’s injury. But it didn’t heighten an existing attitude from a group returning nine starters from last season.

“We believe in our offense and whoever plays, we think they will play well,” Oklahoma junior defensive tackle Gerald McCoy said. “But even though we believe that, we still have to hold our own and do what we have to do. And as of late, we’ve been able to do that.”

The Sooners come into Saturday’s game at No. 17 Miami (ABC, 8 p.m. ET) after notching back-to-back shutouts for the first time since 1987. They have a current scoreless streak of 123 minutes, 3 seconds that ranks as the longest in the nation since allowing a late touchdown against BYU.

The defense’s recent surge coincided when Jones took over. They started it with a strong performance in a 64-0 conquest of Idaho State, as the Bengals did not advance inside the Oklahoma 49 and produced only 44 total yards.

The Sooners continued against Tulsa, which led the nation in total offense the past two seasons and was averaging 41 points a game before meeting Oklahoma. The Sooners notched six sacks and forced three turnovers in a 45-0 statement.

Those efforts have enabled the Sooners to lead the nation in rushing defense (40.7 yards per game), scoring defense (4.7 points per game) and tackles for losses (11.3 per game).

It’s a big turnaround from last year's struggling Oklahoma defense. The Sooners finished 68th in total defense and 58th in scoring defense, which were the worst ratings in Bob Stoops’ coaching tenure. Particularly galling were late collapses in the Sooners’ two losses against Florida and Texas that marked bitter disappointment that carried into this season.

“We didn’t come up with key stops against Texas and Florida when we needed them,” Lewis said. “After last year, we decided we’ve got to be more consistent. Last year we were content to hold them to a couple of touchdowns. That’s totally changed now. We don’t want to give anything up.”

Miami’s athleticism will be the biggest test for the Sooners. And the Hurricanes' struggles at Virginia Tech were an anomaly caused by the wet conditions that helped negate their speed edge.

“It’s going to be a major challenge to go up against a team that in the first couple of games was very explosive and productive,” Stoops said. “I think it’s fair to say that their situation and the circumstances in the Virginia Tech game were difficult to handle. They played in a monsoon, basically, and that changes things.”

The wet conditions caused Miami quarterback Jacory Harris to have trouble with Virginia Tech coordinator Bud Foster’s defensive packages. Harris was sacked three times last week by the Hokies after he was sacked only once in Miami’s first two games.

They will face similar pressure from a balanced Oklahoma defense that has featured eight different players responsible for its 12 sacks so far this season.

"Our goal every week as a defensive line is to be disruptive, get in the backfield, and make quarterbacks feel uncomfortable,” senior defensive end Auston English said. “Those goals won't change this week. We need to continue to build on what we've started this year and hopefully do the same thing this week."

And while Stoops has hinted this season that his current group can become special, the Sooners are focused on more immediate task.

“We want to be a physical defense,” junior free safety Quinton Carter said. “But as far as being compared to defenses from in the past, I guess we have to wait until we get to the end of the season and see what our final legacy is going to be."