NORMAN, Okla. – Josh Heupel waited nearly a decade for this day.

They say revenge serves best as a cold dish, but Heupel’s moment finally arrived on a day when the mercury nearly struck 100 at Heupel’s alma mater.

With the heat sufficiently cranked, Heupel’s No. 7 Tennessee Vols cooked No. 13 Oklahoma, 25-15, at the Palace on the Prairie.

Heupel once thrilled the fans here as the star quarterback on Oklahoma’s last national championship team. He quieted those fans Saturday while making his return triumphant and souring the Sooners’ SEC debut.

"Walking off that field with a win felt pretty good," Heupel said afterward, while flashing the hint of a smile.

Heupel’s the one who got away from Oklahoma – the one Bob Stoops sent away – and he became the one who saved Tennessee from the doldrums.

Heupel rebuilt his career after Stoops fired him from his staff after the 2014 season. He traveled three time zones to do it.

He became a better coach. He even built a defense.

OPINION: If this new Josh Heupel lasts, Tennessee football just might be dangerous

The Sooner Schooner that cruised the field during Heupel’s playing career might as well have rested on flat tires, because it sat motionless for most of the night while the Sooners stumbled, bungled and fumbled on offense.

The Schooner finally shifted into drive after Oklahoma’s two fourth-quarter touchdowns – the only touchdowns Tennessee’s defense has allowed this season.

Josh Heupel, Tennessee show they can win with defense

Tennessee (4-0) assembled a fierce defensive front and unleashed it on the overmatched Sooners.

Oklahoma (3-1) entered the SEC with a defense that looks the part and an offensive line and starting quarterback who are out of their element.

Sooners fans cheered when highlights of Southern California’s loss appeared on the videoboard, but when Lincoln Riley left town, he took OU’s offensive swagger with him.

These Sooners would benefit from a quarterback that either Riley or Heupel developed.

Heupel has molded another talented quarterback. That’s what Heupel does best, from Oklahoma (Sam Bradford) to Missouri (Drew Lock) to Tennessee, with Hendon Hooker and now redshirt freshman Nico Iamaleava.

Iamaleava fires darts, and he puts the ball where his receivers want it. The Sooners’ pass rush gave Iamaleava some trouble in his first career road start, and the Vols encountered trouble protecting him while playing without their top two offensive tackles. Iamaleava, though, connected on enough deep strikes to give the Vols ample scoring opportunities.

Iamaleava received plenty of assistance, too. Dylan Sampson took handoffs on eight consecutive plays on a 46-yard scoring drive, allowing Iamaleava to admire his tailback’s handiwork.

The Vols’ defense bailed their quarterback out of jams, too.

Twice, Oklahoma recovered fumbles after sacking Iamaleava.

And twice, Sooners quarterback Jackson Arnold gave the ball back to Tennessee on the next play.

So bad, Oklahoma’s offense looked, that fans cheered when backup quarterback Michael Hawkins Jr. entered before halftime. Hawkins fumbled his first snap.

That’s the type of night it became for Oklahoma.

Oklahoma shows Josh Heupel respect before game begins

Ten Tennessee players contributed to its 11 tackles for loss. The Vols comfortably won a game in which they punted eight times.

This was no beauty contest. Tennessee’s defense didn’t need it to be.

Heupel infrequently uses his news conferences to send a message, but he emphatically declared after a Week 2 victory that Tennessee holds itself to an elite standard of defense.

“This is the home of Reggie White, Al Wilson, Eric Berry,” Heupel said then.

Now, it’s home to current defenders Keenan Pili, Arion Carter and James Pearce, and they were enough to give Oklahoma fits.

Heupel won the hearts of Vols fans with his 2022 squad that became a blur of offense and a flurry of points.

This team plays more complementary football – not unlike the 2000 Sooners. That season, Heupel’s left arm powered Oklahoma throughout its famous midseason "Red October" tear of Texas, Kansas State and Nebraska before the Sooners’ defense carried the load across the finish line in the national championship against Florida State, while Heupel played through injury.

Heupel went from beloved quarterback to Stoops’ longtime lieutenant, until Stoops fired his co-offensive coordinators, Heupel and Jay Norvell, after a disappointing 2014 season.

That decision derailed Heupel’s chance to become Stoops’ heir.

Stoops’ staff moves worked. Oklahoma’s offense reignited behind Riley, who later replaced Stoops.

Heupel, though, felt a deep cut after getting fired by his alma mater and his former coach. The chip on his shoulder grew. He remains an iconic figure at Oklahoma, and he was treated as such before kickoff.

Oklahoma showed Heupel on the videoboard before kickoff with a message welcoming him back. A pregame video montage included scenes of Heupel celebrating Oklahoma’s national championship 24 years ago after he took the final snap from the victory formation.

Oklahoma treated Heupel with the respect of a legend, and then he showed the Sooners he’s doing just fine without them.

Blake Toppmeyer is the USA TODAY Network's national college football columnist. Email him at BToppmeyer@gannett.com and follow him on Twitter @btoppmeyer.

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This article originally appeared on USA TODAY: Josh Heupel shows Oklahoma football what it's missing as Tennessee rolls