The green light was turned on for No. 1-ranked Harvard-Westlake on Monday in its Mission League opener. Jack Flaherty struck out 12 in five innings and hit a three-run home run in the Wolverines' 16-0 victory over St. Francis.

Brian Ginsberg had three hits and four RBIs. Jackson Grayson was three for three. Sophomore Cameron Deere (10 for 16 on the season) added two hits. Harvard-Westlake is 6-0.

 In a Trinity League opener, Bobby Vasquez hit a three-run home run in Servite's 7-3 victory over St. John Bosco. Rece Goodman outdueled UCLA-bound Griffin Canning to lift Mater Dei past Santa Margarita, 2-1. Each pitcher struck out eight. David Clawson had two hits for the Monarchs.

Chase Strumpf had three hits in JSerra's 7-6 victory over Orange Lutheran. The Lions survived a five-run fourth inning by the Lancers, who received three hits from Josh Morgan, including a two-run double.

El Camino Real received a complete game from Jeremy Polon in a 7-4 win over Village Christian. Josh Garcia threw a complete game with five strikeouts in Chatsworth’s 4-3 win over Arcadia. Jake Ryan went three for three and Riley Conlan had a single and double.

Narbonne defeated Palos Verdes, 3-2. Arnold Solis had two hits.

Huntington Beach defeated Aliso Niguel, 3-2. Birmingham defeated Glendale, 5-1. Jonathan Russomano struck out 10 in six innings. Ray Ruvalcaba had three RBIs.

Etiwanda defeated Burbank, 5-4, behind a complete game from Corey Brown. La Salle rallied from an 8-1 deficit to defeat Granada Hills, 16-9. Ryan Garcia had four hits for La Salle.

Whittier California rallied for a 3-2 win over La Canada. Travis Clark of La Canada threw 6 1/3 scoreless innings.

Eric.sondheimer@latimes.com