Laguna led for most of the third overtime and held on for the two-point win.
"For the most part, I didn't think we played well even, though we won a tough game," Laguna Coach Bret Fleming said. "I think we are still kind of in 'vacation mode.' We didn't execute well offensively or defensively and allowed them (Beckman) to stay in it.
"On the plus side, I thought Tyler Kesler really stepped up and (Jake) Dalke played real well."
Kesler led Laguna with 23 points. Masukawa had 16 points and Dalke finished with nine.
Laguna played its second tournament game Tuesday and faced San Clemente for the second time this season. The Breakers held a four-point lead with just over three minutes to play, but the Tritons, who beat Laguna in the Breakers' season opener at the La Quinta Tournament Nov. 29, scored a 50-43 win.
San Clemente hit critical free throws down the stretch after the Breakers had missed a layup in the final minute that would have tied the score.
Laguna played the majority of the game without Dalke, a sophomore guard, who left early in the first quarter with a sore knee.
Unlike Monday's win over Beckman, Fleming was pleased with his team's showing in defeat.
"I was proud of the kids and how they performed," he said. "I'm not happy that we lost, but felt it was the type of effort that I expect. The kids played hard and we had a chance to win it. It's probably our best effort so far this season."
Masukawa had 12 points, Kesler 10 points, Derek Reigel eight points and sophomore Paul McCabe — who started and "played real well and helped deny their best kid (Dominic Fashing)," Fleming said — scored five points.
The Breakers limited Fashing, who scored 36 points last week against Fountain Valley at the North/South Challenge, to 10 points.
Laguna concludes play at the Century Tournament today at Century High.
The Breakers don't play again until they open Orange Coast League play Jan. 12 at Estancia.
Girls' Water Polo
Laguna is competing today, the final day, at the 16-team Newport Harbor-Corona del Mar Holiday Cup tournament played at both the Newport Harbor and Corona del Mar pools. Sixteen games will be played today starting at 8:30 a.m. at both pools. The tournament concludes with the championship game at approximately 4:05 p.m. at Newport Harbor.