There were four ties and three lead changes in the first half as La Cañada entered halftime up, 25-20, after seeing San Marino's Jasper Hwang drop 11 points in the first half.
La Cañada Coach Tom Hofman said he believed the key to the game was a defensive switch made at the second half when Darrell Dansby guarded Hwang, who only scored two more points after the switch.
"I thought Darrell was the difference because [Hwang] was killing us," Hofman said. "He had like three blocks and [Hwang's] their best player by far."
The first-place matchup carried some extra weight for Dansby.
"We knew this was coming up," Dansby said. "It was a special game, we were talking about this forever. It was a back-and-forth game early, but I did not want to win the game by two."
La Cañada (11-6, 3-0 in league) came out hot in the second half and hit two straight threes. Ryan Lee nailed one from deep on the Spartans' first possession and Jay Srinivasan hit one of his own on La Cañada's next trip down the floor to push the lead to 31-20 less than two minutes into the third quarter.
Srinivasan hit two more three-pointers in the third, widening his team's edge to 36-25 and then 42-25 with 3:07 to go in the quarter. Both those connections were quickly followed with a timeout call from Papadopulos as the home crowd rose to its feet.
"After I hit the first one my confidence usually sky rockets," said Srinivasan, who finished with a game-high 17 points after hitting five threes. "Once it goes in I'm feeling pretty good."