WATCH: No. 2 St. John Bosco shocks No. 1 Mater Dei in high school football Southern California classic

Second-ranked St. John Bosco (Bellflower, Calif.) looked down and beaten. Top-ranked Mater Dei (Santa Ana), which had trailed only a couple of times all season, looked indomitable.

But this is high school football. At its finest.

The Braves, down 28-5 at one point, scored 34 unanswered points starting late in the second quarter to shock Mater Dei 39-34 in the CIF Southern Section Division 1 final Saturday at brisk, packed and loud Cerritos College.

Clemson-bound quarterback DJ Uiagalelei, who has essentially taken a back seat this season to his good friend and Alabama-bound Bryce Young, was sensational, throwing for 444 yards and five touchdowns as the Braves (12-1) advanced to the State Open Division Bowl championship against ninth-ranked De La Salle (Concord) in two weeks. 

The rivalry between the two teams has been as epic as the competition between two of the nation's top-rated quarterbacks.

Young was also sensational, especially early, throwing for 405 yards and five touchdowns. But Bosco made a key halftime adjustment and the Monarchs (12-1) will not win their third straight state championship, or another national crown that seemed firmly in grip.   Afterward, Uiagalelei gave long embraces to his mother, father and other family members. His team had been eliminated the previous two seasons by the Monarchs. He was clearly emotional.

"I'm speechless," Uiagalelei said. "I've been waiting this for three years. I'm just so proud of our seniors, our boys, it's a total team effort today. We came out, said we're not leaving this field with a "W" and that's what we did. We got behind, but we were tired of losing (to Mater Dei)."

A team that had outscored foes 616-192 heading into the game looked primed to bury the Braves, who would not relent. They climbed to within 14-5 on a Logan Loya 33-yard field goal and a safety when Young grounded the ball in the end zone.

But the leading contender for Player of the Year seemed to put the Monarchs back firmly in control, with two more touchdown passes, a 6-yarder to Ware-Hudson and a 21-yarder to Williams, making it 28-5 with four minutes left in the first half.

Like the last time the team's met — a 38-24 Mater Dei victory — Bosco just wouldn't go away. Uiagalelei completed a 6-yard touchdown pass to Kris Hutson just before halftime to make it 28-12. The last meeting, Mater Dei always had an answer. This time around, Bosco's defense stiffened, sacked Young four times and intercepted three times. On offense Uiagalelei, and his deep talented receiving brigade went to work.

He connected on a 26-yard TD pass to Hutson to close to 28-19 and then a 25-yarder to tight end Adam Awaida, making it 28-26 with less than three minutes to go in the third.

After an interception by Bosco defensive end Nathan Burrell, the Braves did the unthinkable. They took the lead 32-28 on an 11-yard touchdown pass to Loya on the first play of the fourth quarter, a third-down play. The Braves missed the extra point.

With all the momentum and a loud and raucous cheering section, the Braves kept pushing. Uiagalelei threw his fifth touchdown pass, the second to Loya, this one a 26-yarder making it 39-28 with 8:52 left.

But Young wasn't finished. He completed a 23-yard touchdown pass to Kyron Ware-Hudson, making it 39-34 with five minutes to go. The two-point conversion pass failed. Mater Dei had two more chances, the first from its own 29 with less than three minutes left, but Bosco's Ma'a Gaoteote sacked Young, forced a fumble and the Braves recovered with 1:30 remaining.

With two timeouts, the Monarchs eventually got one last chance with less than 30 seconds. They got the ball to midfield for one last heave from Young. It was perfect.

In the middle of the end zone, roughly 8-10 of Southern California's finest athletes went up for a jump ball. Hutson, an Oregon commit, came down with it for the Braves, setting off a wild celebration.

This just didn't seem possible. Not because Bosco was inferior, but because Mater Dei had been so perfect all season. The Braves simply willed this one away. Much like Hutson's interception.

This was the fourth straight year the two teams met for the Section title. Bosco won in 2016 and Mater Dei the next two seasons. Each year the Southern California champion went on to win the state Open Division championship over De La Salle.

Earlier this season, Mater Dei beat Bosco 38-24 in Bellflower on Oct. 25. In that game, Young completed 10 passes for 160 yards and three touchdown passes to Cody Epps, who had five touchdown catches in a semifinal win last week. He had only one catch Saturday and was kept out of the end zone.

Bosco coach Jason Negro gushed about his defense afterward. Giving up just one touchdown in the second half to one of the nation's most prolific offenses was beyond expectation.

"They were relentless," Negro told the Los Angeles Times. "That's what you have to do to beat a team like that."