CONCORD >> The Open Division of the California high school basketball playoffs is reserved for the best of the best. To that end, De La Salle already knew where it stood.

But Saturday night, the Spartans went a step further.

They turned up the heat down the stretch in a tightly contested NorCal semifinal, prevailing over visiting Folsom 47-38 even with their best player, Oklahoma-bound Alec Blair, playing on one healthy foot after badly injuring his right ankle a week earlier.

But Blair is a star for a reason.

With De La Salle leading by a point with two minutes to go and the jam-packed home crowd roaring for a big moment, Blair delivered. Just as he has so many times for De La Salle.

Dribbling with a defender on him along the right wing, he unleashed a step-back 3 and then watched it sail.

It hit nothing but net.

Mind you, this is the same guy who shot two airballs from the free-throw line earlier in the game because he couldn’t get enough spring in his legs. But at the game’s most important moment, with third-seeded Folsom still very much alive, Blair hit the jackpot or, as he put it, “money.”

“You kind of knew it was going to go in,” De La Salle coach Marcus Schroeder said. “Sure enough, it went in. That’s just players stepping up. The moment’s never too big for him.”

The moment certainly wasn’t too big for De La Salle. The Spartans (28-4) led the entire way except for two moments in the fourth quarter when the visitors went ahead 36-35 on a bucket by 6-foot-9 Siyahe Siaisiai with 3:51 left and 38-37 on a drive to the hoop by football star Ryder Lyons with 3:01 to go.

Both times, De La Salle quickly responded.

Soon after, the game was over.

The Spartans put away Folsom with a 10-0 closing run, highlighted by Blair’s 3-pointer and textbook defense. Blair led De La Salle with 14 points and four rebounds. David Balogun added 12 points and Braddock Kjellesvig finished with 10 points and six boards.

Blair didn’t practice all week but knew he would play.

He emerged from the locker room 35 minutes before tip-off, fist-bumped teammates who were sitting on the bench and school officials at the scorers’ table, then began putting up some shots.

“I was hurting pretty badly. I was playing on one foot tonight,” Blair said after the game. “I was sitting there that last four minutes, I looked at the clock and said, ‘It’s time.’ ”

For Schroeder and Blair, the game marked an opportunity to take the Spartans beyond the NorCal Open Division semifinal round for the first time since the coach and star player arrived at the Concord school four seasons ago.

Top-seeded Archbishop Riordan, a 64-57 winner over Salesian on Saturday, awaits in the final. The regional championship game will be played Tuesday night at Riordan.

De La Salle will bring a hot streak across the Bay Bridge after beating Dublin, San Ramon Valley and Dougherty Valley to capture the East Bay Athletic League championship, then overpowering defending champion Salesian to win the section’s top division for the first time since the classification was added in 2020.

Next stop for DLS: The NorCal final.

“It’s obviously exciting,” Kjellesvig said. “We’ve worked so hard for this. It’s nice knowing that the work has kind of paid off.”