San Marcos' Christian Yonker loads up to fire a shot past Santa Barbara defender Jack Fulbeck in Tuesday's crosstown battle. (San Marcos Boys Water Polo / Courtesy Photo)

San Marcos boys water polo erupted in the second half en route to a 21-12 win over crosstown rival Santa Barbara High on Tuesday afternoon at San Marcos.

The first quarter was tightly contested, as the two sides exchanged blows back and forth until the Royals held a slim 4-3 lead heading into the second, thanks to three goals from Christian Yonker.

The San Marcos defense then took center stage in the second quarter, holding the Dons scoreless while the offense tacked on four more goals to extend the advantage to 8-3 at halftime.

The Royals’ offense then found its groove in the second half, outscoring Santa Barbara 6-3 in the third quarter as Yonker and Will Stuart each scored twice to bring the lead to 14-6 with one quarter to play.

The Dons found more success in the fourth with six goals in the quarter, including three from Calvin Nelley, but San Marcos netted seven goals of their own to pull away for the 21-12 victory.

Yonker’s five goals led the Royals, while Jake Magid scored four of his own. Brandon Lee scored three times, and both Stuart and Jack Kramer scored twice.

As for the Dons, Lorenzo Russell scored a game-high seven goals and earned three exclusions. Nelley ended the day with four goals and two assists, and West Graham had a goal and a pair of assists.

In the cage, Mason Walsh totaled nine saves and an assist for Santa Barbara.

The Dons will have another crosstown matchup on Wednesday at 3:15 p.m. when they head out to Elings Aquatic Center in Goleta to take on Dos Pueblos.

Noozhawk sports editor Diego Sandoval can be reached at dsandoval@noozhawk.com. Follow Noozhawk Sports on Twitter and Instagram @NoozhawkSports