WACO, Texas — Bryce Petty had done all he could do, bringing Baylor back from 21 points down in the fourth quarter and McLane Stadium back to life.

With 4 seconds left, the Heisman Trophy contender handed it over to the kicker who had made only one of six field-goal attempts coming into the game.

Petty gave a few words of encouragement to Chris Callahan, to focus only on himself and his job — and then the quarterback went over to the sideline and was too nervous to watch as Callahan completed one of the greatest comebacks in Baylor history.

Callahan kicked a 28-yard field goal as time expired and No. 5 Baylor scored 24 points in the final 11 minutes to beat No. 9 TCU 61-58 on Saturday in a crazy Big 12 scorefest.

“I don’t think I could play kicker,” Petty said. “That’s too much pressure.”

Wiping out a 21-point, fourth-quarter deficit, though, seemed like a breeze for Petty. The senior threw six touchdown passes for the Bears (6-0, 3-0), including a 25-yarder to Corey Coleman with 4:42 left in the fourth that tied it at 58. Petty passed for a career-best 510 yards and threw two interceptions.

“He was on tonight,” Baylor coach Art Briles said.

TCU moved to midfield and faced fourth-and-3 from the Baylor 45 with 1:17 left in the fourth. Instead of punting, the Horned Frogs elected to try to keep the ball and end it in regulation.

Horned Frogs coach Gary Patterson used two timeouts trying to decide how to play fourth down.

He said he considered a fake punt.

“We make it ... you have an opportunity to go down and kick a field goal and you win it,” he said. “Their field goal kicker did well today, but he had not kicked well before it got to today.”

Trevone Boykin tossed a sideline fade toward Josh Doctson that the receiver couldn’t come up with. TCU (4-1, 1-1) was looking for a pass interference call on Ryan Reid but didn’t get it and Baylor took over with 1:11 left.

“Basically, you have a guy who has great ball skills and you basically just try to give the guy a chance,” Boykin said of the play. “That’s what we tried to come out and do. The defensive guy just made a better play.”

With the help of a pass interference call on TCU and some good running by Shock Linwood, the Bears marched to the TCU 11 and left it up to Callahan.

“There’s a certain spot I hit on the ball every single time; inside left low. I just focused on that,” said Callahan, who finished 4 for 4 on field goals. “Once I got there, I didn’t even look up. I just took off running because I knew that thing was good.”

The 5-foot-9, 185-pound redshirt freshman set off the first celebration of its kind at Baylor’s brand new, $250 million on-campus stadium. The bright-yellow clad student section poured onto the field to party with their team on the BU logo at midfield.

B.J. Catalon scored three touchdowns, including a 94-yard kickoff return in the first half, for the Horned Frogs. Boykin passed for 287 yards and a score.

All of Petty’s touchdown passes covered at least 25 yards in a wild game filled with huge gains. Baylor finished with 782 total yards, TCU had 485.

A week after taking down Oklahoma, TCU was poised to pull off a second straight upset of a top five team when Marcus Mallet returned an interception 49 yards for a score with 11:38 left to make it 58-41. Save for the purple patches in McLane Stadium, the Bears’ home next to the Brazos River was silent.

No problem.

“I just knew looking at guys’ faces that we were going to come back in that game,” Petty said. “With our offense and the way that we play defense, 21 points isn’t a big deal for us.”

Like a blur, Baylor came back.

It took 59 seconds to cut the lead to 14 with Devin Chafin’s 7-yard touchdown run.

The next Baylor drive took 1:23, covered 92 yards and ended with Petty hitting Antwan Goodley from 28 yards out. 58-51.

Another Baylor stop. Another lightning-strike drive, 91 yards in 59 seconds. Petty to Coleman. Tie game.

Now McLane was rocking. Music blaring. Dancing in the stands and on the sideline with 4:42 left in the fourth.

When it was over, the 110th meeting of TCU and Baylor and the first with both as ranked teams became the highest-scoring game ever between two teams in the AP Top 10. The Bears extended their home winning streak to 13 games and matched the largest comeback in school history.

Baylor is still relatively new to the national stage, the high rankings and title talk. The Bears won the Big 12 last season for the first time, but flamed out in the Fiesta Bowl loss to Central Florida. There’s still some reluctance by the college football world to welcome the Bears into the nation’s elite.

Petty and his teammates seem a little tired of hearing about what they haven’t done.

“For us it’s just another statement game,” he said. “It’s another chance to prove that we’re here to stay.”