NORMAN, OKLA. -- Oklahoma doesn't act crippled up, what with Coach Barry Switzer happily tooling around in a golf cart with a flashing red light on top and a whistle shrieking in his mouth. Defensive back Rickey Dixon yelled, "Tell Nebraska I'm coming!" And even the most vulnerable Sooner, gentle freshman quarterback Charles Thompson, indulged in a little self-confidence.

Oklahoma (10-0) would seem to have little reason for this behavior, having dropped to No. 2 in the national rankings for the first time all season and about to meet the usurper, No. 1 Nebraska, on Saturday in Lincoln, in what is perhaps wishfully referred to as a game of the century. Nebraska (9-0) has displayed an overbearing sense of superiority with the knowledge that Thompson will start in place of Jamelle Holieway, the Cornhuskers threatening to do all sorts of things to his dainty, childish features.

To which the Sooners scoff and Thompson replies coolly. Despite all speculation that their unbeaten season is in jeopardy, that the Cornhuskers will win for the first time in three years and knock them out of the Orange Bowl and national championship, the Sooners persist in acting as if they know something no one else does.

Their knowledge perhaps rests in Thompson, who could be the single most important figure in the game of the season.

"I think it's kind of funny," Thompson said of the remarks being traded. "I like it when people try to taunt me and get in my face."

Thompson's attitude could not be more welcome to the Sooners, who were stunned two weeks ago when Holieway was lost for the season to knee surgery and fullback Lydell Carr also incurred a knee injury that sidelined him, as they struggled to beat Oklahoma State. Then even Switzer came down with strained ligaments when he was hit on the sidelines in a troubled 17-13 victory over Missouri last week.

That was the sorriest kind of luck for a team that once looked almost unassailable, statistically No. 1 in both offense and defense. With two-thirds of their wishbone offense gone, the Sooners must now rely on a redshirt freshman who stands 5 feet 10 and roughly 165 pounds (175 pounds officially, but not nearly). Switzer's voice held disappointment and resignation when he commented, "He's good, but he's not Jamelle Holieway."

How close Thompson can come to Holieway's 1987 performance, which included 925 yards rushing on 142 carries and 548 yards passing for seven touchdowns, will determine much about whether Saturday's game is to be a memorable one for the '80s. Although Thompson has played frequently and effectively in relief of Holieway, the Missouri game was the first time he went four full quarters, and not all of them were steady.

But what few know about Thompson, an 18-year-old amateur break dancer from nearby Lawton, is the potential breadth of his talent. For the season he has 673 yards rushing on 84 carries, third best on the team behind Holieway and Carr, for an average of 7.2 yards, which leads the team. He is reputed to be a better passer than Holieway, having completed 11 of 28 for 207 yards with no interceptions.

But mainly he is stunningly fast, a runner who strikes like heat lightning and once loose cannot be caught. Thompson is secure in that knowledge if nothing else, and it lends him a sneaky and healthy confidence. He contends that while Holieway is the more experienced quarterback, he is potentially more explosive.

"What we lose as far as Jamelle is experience," he said. "But I might be more dangerous. I can go 80 yards, and I can break it at any time."

For a while, Thompson thought he might actually take Holieway's job coming out of spring practice, when the starter sat out with a hand injury. He rapidly displayed a new sense of self in his first words as a starter against Missouri when he told the team, "This is my huddle, not Jamelle Holieway's."

"He's gotten kind of bossy since he became a starter," all-America tight end Keith Jackson said.

But the fact remains that Thompson has been a starter for just one game, and not a very good one. It was the narrowness of the Missouri score that drove Oklahoma out of first place in the rankings, and it contained unsettling signs like four fumbles. Thompson's operation of the offense was frequently hurried and unwise, one thing that contributed to the turnovers and the dubious score.

Against Nebraska's polished Steve Taylor, Thompson may look particularly inexperienced. The Sooners' wishbone offense has always yielded more than the usual amount of turnovers, but this season they have fumbled a total of 50 times, fortunate to lose only 19 of them. The Cornhuskers will not be so generous with errant pitchouts, and turnovers could mean a blowout.

"Sometimes inexperienced kids get out there and go helter-skelter on you," Switzer said. "That's what Steve Taylor won't do. It's thousands of little things like that."

Thompson feels challenged enough already to have lost some sleep. He spent most of Monday night going over various possible outcomes in the game. And he has also expressed the slightest sign of displeasure at having so much importance placed on his exceedingly skinny young presence.

"Sometimes I think everybody is trying to put it on my shoulders," he said. "There's 10 other guys with shirts that say Sooners."

That fact is also a source of Oklahoma's surprising confidence. Its defense gives up just one touchdown and 205 yards a game, while at the same time the Sooners are averaging 505 yards a game in offense, most of it behind a huge veteran line that has told Thompson they will "block so hard a baby could run though there," he said.

With Thompson's youth also comes ignorance, but in this case it's not such a bad thing. Having never played in a Nebraska game, he is blissfully unaware of what "11 hostile people" as Switzer calls Nebraska's defense, might inflict on him.

"I've never even been to Lincoln," he said. "It's all new to me."