Most teams don’t come back from two-touchdown deficits against Loyola.

Most teams don’t have the grit and gumption of Providence.

The Celtics’ second-half rally to produce a stirring 21-20 victory over the twice-defending 8A champions in the Catholic League crossover will eventually be the stuff of legend.

On Friday night, it was reality.

The outcome – perhaps Providence’s biggest victory since its last state title in 2004 – makes the 5A Celtics (5-2) a team to deal with once the playoffs start.

Heroes weren’t hard to find in the postgame celebration, one capped by a 100-decibel Hail Mary.

There was Broden Mackert, a junior who ran for a pair of touchdowns among his 24 carries for 142 yards.

There was his offensive line, a cadre featuring Bryce Tencza, Henry Kalis, Gunner Thormeyer, Ryan Lenahan and Anthony Santori III, smiling and sweating simultaneously.

There was Collin Shedwill, a junior linebacker whose sack of Loyola quarterback Matthew Lee on the Ramblers’ two-point conversion attempt with 20.3 seconds remaining set the final score and set off the celebration.

“I needed to make a play for my team, and that’s what I did,” Shedwill said. “It means more than anything. They predicted we had a 13% chance of winning coming into this game. We came out here and proved them wrong.

“We got it done.”

And for coach Tyler Plantz, who played on the last Celtics team to beat the Ramblers – in the autumn of 2009 – it was also sweet.

“It’s a testament to a lot of hard work,” Plantz said. “This is the first group I came in with. We’ve had some ups and downs, but the way they worked and believed in each other, it’s been awesome. The trust they’ve put into the staff and committed to each other, it’s awesome.”

Trailing 14-7 at the half, Providence got scores on Dominic Vita’s 8-yard pass to DeAngelo Coates on the opening drive of the second quarter, a 13-play possession, and from Mackert a 3-yard burst off left end on his 23rd carry of the night to make it 21-14 with 1:14 remaining.

“This means everything,” said Mackert, who ran for 142 yards. “We came in knowing we were going to run the rock. No matter the rank (of the opponent), we’ve got to fight.

“I trust those guys,” Mackert said of his offensive line. “They give me every yard.”

He gobbled up a few by himself, dragging Ramblers tacklers along for the ride.

The Ramblers broke to a 14-0 lead on first-half touchdowns by sophomore Jordan McKinley, a 15-yard reception of fellow sophomore Lee’s pinpoint pass, and a 5-yard touchdown run by Melo Maldonado, still another sophomore.

But that early surge faded thanks to Providence’s defense. It held the Ramblers on their next series, and Providence took advantage of an 8-yard punt to mount a three-play, 22-yard scoring drive late in the second, Mackert crashing in from the 5 to halve the margin to seven points at the half.

It was just the start. Providence would run 44 plays in the second half to Loyola’s 18, a half-dozen of which came on the Ramblers’ last drive, which culminated in Lee’s 25-yard touchdown pass to Jay Haughey. But going for two points and the win proved fatal thanks to Shedwill’s burst through the line.

“The job’s not finished,” Shedwill said. “At 5-2, that’s not good enough for us.”

“Loyola did a great job in the first half scheming up our defense,” Plantz said. “We made a quick adjustment at the half, looked at a little bit of tape, and the kids said, ‘Perfect – easy to make.’ These guys’ intelligence and understanding of the game is pretty awesome.”

Loyola drops to 4-2, the other loss at the hands of Brother Rice.