The Harvard-Westlake High boys’ basketball team, led...

The Harvard-Westlake High boys’ basketball team, led by twins Jarron and Jason Collins, begins defense of its Southern Section Division III-A title by playing host to Northview in a playoff opener at 7:30 tonight.

Montclair Prep, the other defending Southern Section champion from the region, plays host to Boron in a Division V-AA game at 7:30. The Mounties are led by guard Rocky Steryo, a three-point shooting threat who averages 22.9 points.

Other events involving teams from the region include:

College baseball: At 2 p.m., Cal State Fullerton at Pepperdine. At 2:30 p.m., Whittier at Cal Lutheran.

Women’s basketball: At 7 p.m., San Francisco at Pepperdine. At 7:30 p.m., Cal Lutheran at Redlands.

College softball: At 2 p.m., Occidental at Cal Lutheran. All day, Cal State Northridge in San Diego State tournament.

College swimming: At 2:30 p.m., Valley at Citrus.

Men’s tennis: At 2 p.m., Cal Lutheran at Redlands.

Women’s tennis: At 2 p.m., Redlands at Cal Lutheran.

College track and field: All day, Cal State Northridge in Big Sky Conference Indoor championships at Walkup Skydome, Flagstaff, Ariz.

Boys’ basketball: At 7:30 p.m., City Section first-round playoffs: Taft at Crenshaw, Kennedy at Canoga Park, Monroe at Westchester, Cleveland at Carson, Roosevelt at Poly, University at Birmingham, Granada Hills at Eagle Rock, San Pedro at San Fernando, Huntington Park at Sylmar.

Southern Section first-round playoffs: Leuzinger at Channel Islands, Santa Monica at Palmdale, Highland at Simi Valley, Hoover at Ayala, Warren at Hart, Royal at Rio Mesa, Buena at Antelope Valley, Valencia at Compton, Ventura at Righetti, Santa Barbara at Burbank, Agoura at Moorpark, Burroughs at Newbury Park, Calabasas at Dos Pueblos, La Canada at Morningside, Chaminade at Bishop Montgomery, Crespi at Oak Park, St. Paul at Paraclete, Village Christian at Crossroads, St. Monica at L.A. Baptist, High Desert at Bell-Jeff, Buckley at Thacher, Holy Martyrs at Bishop Diego, Grace Brethren at Cornerstone Christian, Antelope Valley Christian at Rolling Hills Prep, Santa Clarita Christian at Pilgrim, Lancaster Bethel Christian at Immanuel Christian, Landmark West at Rio Hondo Prep.

Girls’ basketball: City Section first-round playoffs: At 5:30 p.m., Grant at Palisades, Fairfax at Poly. At 7:30 p.m., El Camino Real at North Hollywood, Dorsey at Kennedy, Birmingham at Sherman Oaks CES, Granada Hills at Hamilton.

Boys’ soccer: At 3 p.m., City Section first-round playoffs: Crenshaw at Reseda, El Camino Real at Lincoln, Chatsworth at Hollywood, Marshall at Sherman Oaks CES, North Hollywood at Bell, Verdugo Hills at Los Angeles, Kennedy at Hamilton, Cleveland at Poly, Grant at Birmingham.

Southern Section first-round playoffs: Arroyo Grande at Simi Valley, Camarillo at Rio Mesa, Palmdale at Royal, Saugus at Buena, Atascadero at Burroughs, Bosco Tech at Calabasas, Rosemead at Moorpark, Valencia at El Monte, Notre Dame at Oak Park, Crespi at Fillmore, Carpinteria at Santa Ynez, Morningside at La Canada, Kilpatrick at Windward, Campbell Hall at Maranatha, Village Christian at Desert Christian.

Girls’ soccer: At 3 p.m., City Section first-round playoffs: Palisades at El Camino Real, Grant at Granada Hills.

High school wrestling: At 10 a.m., Southern Section Division I finals at Canyon Springs High, Division II finals at Westlake High, Division IV finals at Santiago High.