LUBBOCK, Texas — Texas Tech coach Mike Leach knew something had to change when the Red Raiders rolled up 718 yards last year against Oklahoma State — and lost.

The offensive wizard's days of merely tolerating defense were over. It turned out that all he had to do to fix things was walk a few doors down the hall to the office of a coach who came with him to Lubbock seven years earlier.

Ruffin McNeill's promotion to defensive coordinator after that deflating 49-45 defeat transformed the Texas Tech defense perhaps more than Leach could have imagined. The No. 2 Red Raiders won't be confused with the defensive stalwarts of the Southeastern Conference, but they don't have to be when they pass for 400-plus yards and score at least 40 points nearly every week.

Across-the-board improvement by the defense under McNeill played a major role in positioning Texas Tech (10-0) for a run at the national championship, the next step coming Saturday at No. 5 Oklahoma (9-1).

McNeill's plan wasn't complicated. In fact, it was simple — as in simplifying schemes, defensive lineman Jake Ratliff said.

"He wanted us to quit thinking and go play football," Ratliff said. "That's the way it should be: when in doubt, just go attack. There's no thinking involved."

Ratliff praised McNeill's predecessor, Lyle Setencich, whose hiring five years ago led to a similar uptick in Tech's defensive performance. The Red Raiders held pretty steady on defense under the man who gave Leach his first college coaching job 20 years ago.

But there was something different about that day in Stillwater, Okla. Perhaps it was Oklahoma State having three 100-yard rushers in a game for the first time ever — and gaining 366 yards on the ground — that led Leach to question the toughness of the Tech defenders.

A day later, Setencich stepped down for personal reasons, and Leach made Ruffin the interim defensive coordinator.

In their final nine games, the Red Raiders went from ninth to first in total defense in the Big 12 (405.5 yards to 347.6); 10th to fourth in scoring defense (28.2 points to 24.9); seventh to first in pass defense (206.8 yards to 180.2); and 11th to eighth in rush defense (198.8 yards to 167.3 yards).

"The biggest thing is Ruffin's passion about football," Leach said. "I think he makes the rest of the staff passionate about football as well as the players. They are all out there excited to play, which I think is really key."

The defensive numbers aren't much different from those in several seasons under Setencich. But the record is. The two biggest games of the season — back-to-back wins over then-No. 1 Texas and Oklahoma State that put Texas Tech front and center in the national title chase — each had a different stamp from the defense.

Against the Longhorns, Tech scored the game's first points on a safety and dominated defensively most of the first half. Texas finally started moving the ball and took the lead late in the fourth quarter, but Tech's trusty offense came through on Graham Harrell's winning 28-yard touchdown pass to Michael Crabtree with 1 second left.

A week later, the Red Raiders had their best defensive game of the season, holding the Cowboys well below their season averages in all phases for a 52-20 victory.

"They listen as well as any team I've been around," Ruffin said. "This team has really a great ability to focus on a particular task."

Of course, the Red Raiders have some talent, too. Defensive backs Darcel McBath and Daniel Charbonnet have combined for 11 of Tech's 16 interceptions, the team total ranking ninth nationally. That secondary also has shown a knack for shutting down the opposing team's top receivers.

Oklahoma State's Dez Bryant had four catches for 86 yards with no touchdowns a week after catching nine balls for 171 yards and a career-high four scores. Texas receiver Jordan Shipley had 42 receiving yards, less than half his average, and Kansas' Dezmon Briscoe had eight catches for 55 yards a week after setting school records with 12 receptions for 269 yards.

As good as all that sounds, Ruffin is looking for more.

"I don't think we've played our best yet," he said. "We've got a lot of room to grow and improve."

Ruffin probably had Oklahoma's Sam Bradford in mind when he said that. Those Tech shutdown trends will be tested by a quarterback who leads the nation with 38 touchdown passes, two shy of Jason White's school record from his 2003 Heisman Trophy season.

Tech's most impressive defensive stat will be tested, too. The Red Raiders rank 20th nationally in run defense at 107.4 yards per game, and Oklahoma features two of the top three rushers in the Big 12 in DeMarco Murray (804 yards, 11 touchdowns) and Chris Brown (782 yards, 12 scores).

The players trust McNeill to have the answers.

"He definitely knows what he's doing outside just the Xs and Os part," Charbonnet said. "He's really good at mentally getting you prepared."

Ruffin, who turned 50 last month, has two grown daughters and exudes a grandfatherly presence from the sideline. It's certainly a contrast to the amped-up animation of his counterpart at Texas, 37-year-old Will Muschamp. But Ratliff said not to let looks deceive.

"He is going to be the first one to get in your face and tell you what you're doing wrong and he's going to be the first one to come slap you on the back too and tell you, 'Good job,"' Ratliff said. "He adds a little spark to our defense, and I think that's what we needed."