CONCORD — De La Salle doesn’t lose back-to-back games.

After a historic loss last week — its first to a regional opponent in 30 years — the Spartans responded with a statement win, 49-21, over Cathedral Catholic, one of the San Diego section’s top teams.

Coach Justin Alumbaugh challenges the Spartans to check four boxes each week: discipline, effort, passion and unity. They notched all four Friday night after missing on all counts last week against St. Francis, Alumbaugh said.

“If we played like we did last week, they would have beat us,” Alumbaugh said.

Alumbaugh gave the Spartans an attitude check all week in practice.

“We realized we have to get our (expletive) together, basically,” linebacker Dominie Perkins said.

Early on, it appeared as if Cathedral Catholic could have been sending the Spartans to their second straight loss — something that has never happened in the regular season since Alumbaugh took over the program in 2013.

Quarterback Luke Dermon threw an interception that led to the Dons’ first touchdown. The Spartans were in a 14-0 hole by the end of the first quarter, after Cathedral marched 12 plays for its second score.

But the game changed in a flash.

CONCORD, CA – SEPT. 17: De La Salle’s Charles Greer (29) runs for an 80-yard touchdown run against Cathedral Catholic in the third quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 

That flash, why, it could have been Charles Greer streaking past defenders on one of his 19 rushing attempts for 237 yards — a top-20 all-time rushing performance in De La Salle history. Or it could have been Journey McKoy or Zeke Berry returning one of three interceptions.

In just over 5 minutes of game time, De La Salle turned a 14-7 deficit into a 28-14 advantage and never trailed again.

McKoy and Berry came down with a pair of interceptions that set up first-half scores.

McKoy returned his first of two interceptions to the Cathedral 11-yard line, where Greer took it in for in for six on the Spartans’ next offensive play to tie the game at 14 with just over 8 minutes left in the second quarter.

Under pressure two drives later, Cathedral quarterback Charlie Mirer floated a pass attempt to Rex Haynes down the sideline, but Berry made a play on the under-thrown pass, then returned it 22 yards to the Cathedral 37. Greer, you guessed it, took the next handoff 37 yards into the end zone, capping the Spartans’ 28-0 second quarter with 2:24 left.

In between, Berry took the first handoff following a Dons punt 44 yards to the house. The University of Arizona commit finished with 109 yards on the ground in addition to his interception on defense.

It felt even better, he said, to do it for an audience that included Cal coach Justin Wilcox, one of his suitors who has recruited a number of Spartans to Berkeley. The main attraction for the Golden Bears head coach was Cathedral’s defensive line star Jaxson Moi, who’s committed to attend Berkeley next fall.

“Oh, does it (feel good)? It does so much,” Berry said. “It’s good playing well in front of any college coach. I play the game because I love game. Him wanting me to play in his program and me balling out in front of him, it just shows that I can play at any level.”

CONCORD, CA – SEPT. 17: De La Salle’s Zeke Berry (10) gestures to the student section after intercepting a pass against Cathedral Catholic in the second quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 

Mirer and Haynes — sons of former NFL players with college offers themselves — were also held in check to the tune of 71 total passing yards. Cathedral running back Lucky Sutton needed 29 attempts to reach 156 yards rushing.

The Spartans had five scoring drives of only one play — three touchdowns set up by turnovers and two more on quick-strike sprints of 44 and 80 yards.

It was the second straight week that the Spartans allowed their opponent to open a quick two-score advantage.

“We spotted St. Francis 14, and we spotted these guys 14,” Alumbaugh said. “If we spot St. Frances Academy or Folsom — or the EBAL schools — we can’t spot people 14. That we have to change.”

Last week, the Spartans climbed out of the hole but weren’t able to pull out the game. On Friday, they left no doubt.

The Dons were ranked No. 8 in California, according to CalPreps, as well as the top team in the San Diego Section.

CONCORD, CA – SEPT. 17: Cathedral Catholic’s Lucky Sutton (7) fumbles the ball and is recovered by De La Salle in the third quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 

Cathedral’s only scoring play after the first quarter came after a botched handoff early the third quarter resulted in the Dons gaining possession at De La Salle’s 41-yard line. Two plays later, Mirer connected with tight end Max Bayles for a 34-yard score.

Off went Charles Greer, 80 yards past the pylon on the Spartans next play from scrimmage, halting any momentum the Dons had briefly regained. Thirteen seconds had expired on the game clock.

Senior defensive lineman JJ Tofaeono recovered a fumble at the Dons’ 1-yard line on their next possession, and Dermon piled in a play later for the final touchdown, 49-21.

“We had our backs against the wall,” Alumbaugh said. “Our kids showed a lot of resolve.”

CONCORD, CA – SEPT. 17: De La Salle’s Charles Greer (29) is mobbed by his teammates and students after scoring an 80-yard touchdown run against Cathedral Catholic in the third quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: De La Salle’s Charles Greer (29) scores a touchdown against Cathedral Catholic in the second quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: De La Salle’s AJ Bianchina (27) runs in for a touchdown against Cathedral Catholic in the second quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: De La Salle head coach Justin Alumbaugh coaches from the sideline against Cathedral Catholic in the second quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: De La Salle quarterback Luke Dermon (16) looks to throw while being pressured by Cathedral Catholic’s Jaxson Moi (51) in the first quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: Cathedral Catholic quarterback Charlie Mirer (12) reacts after throwing an interception in the third quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group) 
CONCORD, CA – SEPT. 17: Cathedral Catholic quarterback Charlie Mirer (12) recovers his own fumble in the second quarter of their game at De La Salle High School in Concord, Calif., on Friday, Sept. 17, 2021. (Jose Carlos Fajardo/Bay Area News Group)