The Falcons improved to 7-2, while the Lancers fell to 6-2. It marked the only time that the teams will meet in the regular season, though a playoff match might loom in November.
"La Serna is definitely one of the top two teams in the division," Crescenta Valley Coach Jan Sakonju said. "This was a battle to see where we are at right now and we were the better team [Tuesday].
"Everyday you need to be learning about something and we needed to play our 'A' game today."
The Falcons' defense held the Lancers' offense in check throughout most of the match. Crescenta Valley limited La Serna to three goals in the final three quarters and forced it to take long-distance shots that Colvin had little trouble stopping.
Colvin, a reigning All-Area first-team member, finished with nine saves. Colvin, who stopped a five-meter shot by Aaron Valdes midway through the first quarter, collected six second-half saves.
"Rane came through in goal and our perimeter defenders were patent and avoided giving easy fouls," Sakonju said. "We had good hustle and good movement to the ball."
Dearman's first goal gave Crescenta Valley a 3-2 lead with 5:57 left in the second quarter. He later collected a pair of third-quarter goals, the second one giving Crescenta Valley a 9-4 advantage with 59 seconds left.
"You go out there and treat every game like it's a normal game," Dearman said. "You have to play as hard as you can and try not to get sucked into all the hype.
"We were able to stay calm and we had everybody on the same page. We knew that La Serna has some good players."
Crescenta Valley received a pair of goals from Louis Wojciechowski and one apiece from Josh Chi, Jack Snyder, Nick Rapose and Robby Ruzicka. Wojciechowski's goal gave the Falcons a 6-3 lead with 39 seconds left in the second quarter. His first goal came with the man-advantage and put the Falcons up, 5-2, with 4:27 left in the first half.
The Lancers got two goals each from Valdes and Kevin Rubio.