NORMAN (AP) — To compare Bob Stoops and Mike Leach at first seems like a study in opposites.

One is the son of a football coach who built his reputation on a stingy, aggressive defense and puts forth a straight-laced persona that rarely cracks.

The other started out admiring the game from the stands, got his law degree before rising in the coaching ranks and then constructed the most productive offense of the past decade. Until his team’s first legitimate bid for a national title this year, his quirky love of pirates and assortment of non-football interests made him something of a class clown in the Big 12.

Their paths intersected for only a year, but it left a profound impact on both Stoops’ program at Oklahoma and Leach’s at Texas Tech. The two meet again Saturday in a game loaded with national championship implications.

No. 2 Texas Tech (10-0, 6-0 Big 12) can clinch the Big 12 South with a victory and also move a significant step closer to the BCS title game, while the fifth-ranked Sooners (9-1, 5-1) can get back in both races if Stoops can beat his former assistant for the fifth straight time in Norman.

Stoops and Leach united in 1999 to turn around an Oklahoma program that had fallen on hard times. Stoops, who had helped Steve Spurrier win a national title as the defensive coordinator at Florida, would need to hire his first offensive coordinator and among the things he considered was who he’d had the most trouble defending.

He came up with Hal Mumme, whose offenses had been smashing records at Kentucky.

“I couldn’t get him to come with me, so I figured I might as well try the guy that’s been with him the longest and try and to do the same things here,” Stoops said.

“There wasn’t anyone else that I had seen that was like that, and I felt it would be different here as well, that it would give us an advantage maybe that people weren’t familiar with.”

Leach, who’d been with Mumme through early days at Iowa Wesleyan and Valdosta State before spending two years as his offensive coordinator at Kentucky, was caught off-guard when Stoops came calling.

“I was pretty surprised. And it all happened pretty fast, though, because he got the job pretty quickly and I didn’t have any idea that he’d call me,” Leach said.

The two knew each other mainly through pregame conversations when Kentucky and Florida would play, but together they started something special at Oklahoma.

Leach instituted his spread offense opposite Stoops’ sturdy defense, and the Sooners were almost instantly back on the map. Even though Leach left after only one season to take over at Texas Tech, Oklahoma was headed in the right direction — and quickly. In 2000, Stoops won his only national championship with the Sooners.

Among the keys to maintaining that instant success was the stable of quarterbacks that Leach was able to attract to Norman with his wide-open attack. Josh Heupel, Nate Hybl and Jason White — who ended up winning the 2003 Heisman Trophy — were the quarterbacks for Stoops’ first six seasons at Oklahoma.

“That part of it really got us going as far as having some quarterback play and being able to attract other quarterbacks like Sam Bradford now,” Stoops said.