Alemany defeats San Fernando 43-0 in Casey Clausen’s coaching debut

It was 19 years ago when I last saw Casey Clausen on the sideline at Mission Hills Alemany High. It was his final high school game. He lost to Matt Grootegoed and Santa Ana Mater Dei 45-14 in the 1999 quarterfinals of the Division 1 playoffs. He was in tears afterward but the maturity he showed shaking hands, thanking teammates and doing interviews during an emotional ending provided a sneak peek at the years ahead.

He’d go on to start 44 of 47 games at quarterback for Tennessee. In 2014, he became head coach at Calabasas, which had been 0-10 the previous year. In four seasons, his teams won two Southern Section championships. Now he’s back at Alemany as head coach. He’s married and the father of three children, ages 5, 21/2 and 2 months. His brother Rick is a key assistant and he also gets help from brother Jimmy, a former NFL quarterback.

On Friday night in his coaching debut for the Warriors, Alemany rolled to a 43-0 victory over San Fernando.

“We are young and green but we’ll continue to get better,” Clausen said.

Clausen is trying to build with young players and he’s got plenty. Kevin Green, a freshman receiver and the younger brother of former Valencia standout Mykael Wright, could be a star in the making. He was dazzling at times when quarterback Miller Moss got him the ball, making four catches for 67 yards. Sophomore Jaylin Smith had a 65-yard kickoff return for a touchdown. Moss, a sophomore who started several games as a freshman at Loyola, completed 20 of 34 passes for 245 yards and two touchdowns. Senior running back Omari Garry scored three touchdowns. He caught a 14-yard touchdown pass and had TD runs. Sophomore receiver Alonzo Fontenette had five catches for 82 yards.

The defense, led by three sacks from Trevor Ojoh, recorded two safeties and made a supposedly good San Fernando rushing attack look nonexistent. Alemany led 14-0 at halftime and broke the game open with a 22-point third quarter.

San Fernando should fit in well in the City Section competition behind Narbonne. The Tigers’ defense was effective at times, led by linebacker Nehemiah Thompson, who might have been the best player on the field. “He’s special,” Clausen said.

Thompson had a sack, was in on numerous tackles, blocked an extra point and was a true pest all night. But the Tigers’ offense was miserable, and that was a problem for many City Section teams Friday. There’s been a growing talent drain to private and charter schools. And scores told the story.

West Covina South Hills defeated Crenshaw 37-6; Long Beach Poly defeated Dorsey 37-8; Carson lost to Long Beach Millikan 7-3; Oxnard defeated Granada Hills 56-6; Banning lost to Cathedral 41-14; Sylmar lost to Encino Crespi 34-6. Then there was some hope. Birmingham defeated Studio City Harvard-Westlake 30-21 and Garfield knocked off Montebello 28-7.

eric.sondheimer@latimes.com

Twitter: @latsondheimer