MIAMI GARDENS, Fla. — Standing on the sideline last year in Orlando watching Oklahoma take a 40-6 pounding from Clemson in the Russell Athletic Bowl, Baker Mayfield’s competitive nature was offended. He still was a veritable unknown to the Sooners, a walk-on transfer from Texas Tech waiting for the opportunity to impose his will on a new bunch of teammates as their quarterback.

“It was hard to watch,” Mayfield said Tuesday at Orange Bowl media day before the No. 4 Sooners (11-1) meet No. 1 Clemson (13-0) in a rematch Thursday in the College Football Playoff semifinals. “They flat-out embarrassed us. The attitude we had on our sideline was not great.

“What I took away was the disappointment of how we carried ourselves in that game. That’s what we use as fuel. We’re not going to let that happen again.”

That frank assessment is typical Mayfield. He takes pride in his down-to-earth underpinnings, and in the chip he carries on his shoulder after being shunned by TCU for a scholarship he believed had been promised and then by Texas Tech coach Kliff Kingsbury, who took away the starting job after Mayfield suffered a midseason injury in 2013, prompting the move to OU.

The Sooners had a quarterback in Trevor Knight, but last season’s 8-5 record loosened his grip, and Mayfield took charge with a combination of charisma and talent during spring football.

“He wasn’t a walk-on for long once we saw him play,” coach Bob Stoops said. “We knew we weren’t going to be able to go out and recruit a guy like this. Charisma is part of his game. There’s a natural joy to him and how he competes that rubs off on everybody.

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“But you can’t ignore the talent, either. You see how quick his arm is. He can throw from any angle, and he has the ability to scramble.”

Clemson defensive end Shaq Lawson said the Tigers haven’t bothered watching video of last year’s bowl blowout because of the dramatic switch to Mayfield at quarterback and the change to offensive coordinator Lincoln Riley, who installed a version of the “air raid” offense Mayfield ran at Texas Tech but with some alterations to involve running backs Samaje Perine and Joe Mixon.

But the man who makes it work is Mayfield, who passed for 3,389 yards and 35 touchdowns while throwing a mere five interceptions.

“He’s like Johnny Manziel,” Lawson said of Mayfield. “He likes to extend plays and keep the drive alive.”

Mayfield’s improvisational skills can stretch a defense to its limits.

“Pressure’s not really a factor with Baker,” OU wide receiver Sterling Shepard said. “He does a great job of getting out of the pocket and making plays. His decisions with the ball are just spot-on it seems like.”

Mayfield’s personality has been infectious. When Mayfield was off on the postseason awards circuit, Shepard said: “Everybody noticed it. Everybody loves being around the guy on and off the field. He brings the energy every week.”

Following the Sooners’ only loss to Texas in October, it was Mayfield who dialed up the intensity in practice and built camaraderie with his playful yet purposeful jibes with the Sooners’ defense.

“When he’s scrambling around, he’s talking trash,” defensive end Charles Tapper said of Mayfield. “He just brings the best out of you. You want to tackle him so bad.”

That heightened focus resulted in seven straight wins to make the playoffs, and the only close one was a one-point win over TCU when Mayfield suffered a concussion with a 23-9 lead. The Sooners come into college football’s final four as the hot team with the hot quarterback.

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If anyone has that certain indefinable something that can lift a whole team to greatness, it’s Mayfield.

“I’m real with those guys, and that means they can trust me,” Mayfield said. “They know I’m not putting on a front, so, they play harder for me, and I’m going to play 110 percent for them. There’s no doubt about that.”