LOS ANGELES — They stood, for minutes, inside a maelstrom, the Galen Center the loudest it had ever been to Eric Musselman’s ears. Double-digit lead had been whittled away by this motley crew of USC transfer-portal imports, and they could all feel it — the chance at an immortal crosstown win in an instant classic.

UCLA’s Mick Cronin kept his arm cycling on the sidelines, waving in an army of new baby-blue Bruins to try to stop the bleeding as minutes waned. USC guard Wesley Yates III nodded his head at any teammate in the vicinity, giddy, after a layup cut UCLA’s lead to two with 2:39 left. Fiery forward Saint Thomas grabbed a rebound and was fouled, to follow, setting up a pair of free throws that’d finally give USC the lead in this matchup of grit against grit. On the baseline, he nodded as Galen roared, slapping hands with USC assistant athletic director Gavin Morris.

Then Thomas clanked a free throw off the rim. Once. Twice. And on the other end, with a minute left and a one-point lead, UCLA guard Sebastian Mack launched a moonbeam from the wing — arcing sleepily over a crowd that had berated the Bruins all night.

It dropped, and any chance at a Trojans crosstown comeback vanished with it, Cronin and Mack and UCLA (15-6, 6-4 Big Ten) putting away an upstart USC squad 82-76 in first-year head coach Musselman’s first taste of the Los Angeles rivalry.

Mack finished with 14 points on 4-of-7 shooting for UCLA, winners of its last four games. Forward Eric Dailey Jr. added 16 timely points to lead the Bruins, while USC backup big Rashaun Agee led the Trojans with 21.

In the summer, a couple short months into the process of figuring out where exactly his puzzle-piece roster fit, Musselman admitted in one of his first media availabilities that USC was “probably a little thin” at both point guard and center. His floor general was 6-foot-6 Desmond Claude, who’d mainly played a combo-guard role in a previous stop at Xavier. His center was 6-10 Josh Cohen, a few inches shorter than most of the behemoth bigs in the Big Ten.

Seven months later, Cronin brought a scythe of a gameplan into the Galen Center, a veteran coach and a veteran program slashing away at the weaknesses in USC’s roster makeup. Not a few minutes in, and pesky Bruins guard Skyy Clark was picking up Claude full-court, as Cronin flapped his wings in motioning for UCLA defenders to trap Claude and limit the airspace of any ball handler near the top of the key.

For stretches in the first half, it played to perfection, turnover-prone but top-scorer Claude limited to just three points as his driving lanes were smothered. After a rim-running layup from UCLA’s William Kyle III, USC’s Yates caught a pass deep in the corner and disappeared into a trap of baby-blue Bruins jerseys, stepping out bounds; after a pass the next possession slipped through wing Chibuzo Agbo Jr.’s hands, USC had six early turnovers within the first 11 minutes.

USC hung around, for the rest of the first half, despite not holding a single lead since 17 minutes in. Cronin’s pressure left wide-open gaps for shooters in the corners and at the top of the key, and a variety of Trojans snipers took aim. Yates, who finished with 19 points in continuing to assert himself as a future cornerstone of Musselman’s program, knocked down a couple triples from the corner. Forward Saint Thomas, perhaps the only person on the hardwood Monday night buzzing with more fire than Cronin, nailed a couple more from the top of the key and let anyone within shouting distance know about it.

The Trojans, though, went into the half down five, thanks to a bevy of too-easy drives to the rim in a UCLA first-half shooting a baffling 68% from the floor. And after a quiet first frame from 7-foot-3 big Aday Mara, starting in place of injured Bruins top scorer Tyler Bilodeau, the blossoming Mara lay waste to an undersized USC roster.

A year ago, the Spanish giant was an afterthought in L.A.’s crosstown clash, playing a combined total of 20 minutes in two matchups. On Monday night, he was the difference-maker. Early in the second half, Thomas drove baseline — Mara away swatted his attempted layup, only for Thomas to recover and go back up and get swatted again by Mara, the ball careening off Thomas’s noggin in insult to injury. A few seconds later, UCLA’s center stuck his tree-branch arm out to thin air for a pass from Dylan Andrews for a pretty layup; a tip-in layup and a fadeaway jumper came just a few minutes later, giving the Bruins an authoritative 11-point lead.

Mara’s contemporary in cardinal-in-red, though, gave him all he could handle as the Trojans hung around. Rashaun Agee stands 6-foot-8, and looks at times closer to 6-6; for years at Bowling Green before USC, still, he’d been battling opposing bigs, and faced one of his toughest Big Ten matchups yet off the bench in a player seven inches taller in Mara. Unafraid, and undeterred by two early airballs, Agee went rollicking down the lane to finish with 15 second-half points; an and-one layup cut UCLA’s lead down to three with five minutes to play, setting the stage for a gut-wrenching finish.