Mazur, however, was also a force with the bat, belting three doubles, one each in the first three innings, to pace the designated home team, which scored 11 runs through three.
Mazur, who Costa Mesa Manager Randy Wood said had "a little extra hitting," after going just one for six in his first two tournament games, drove in three and scored one to help his own cause.
Shortstop Matty Palma had two hits and a walk, scored three times and had a pair of stolen bases to go with his stellar defense. Palma was in the middle of a one-six-three double play that ended the Fountain Valley fifth inning.
Charlie Godshall and Brian Rodriguez had RBI singles in the first inning, while Godshall also had a stolen base and a run to maximize his only plate appearance.
Carson Letterman pitched two scoreless innings, allowing just one hit.
He also drove in a run in the first and later stole a base and scored in the fifth.
Ian Robbs had an RBI double, while Colby Arensdorf and Trevor Brown each added one hit to the winners' total of 10.
Jack Sheets walked twice and scored both times and was a wall behind the plate.
Bradley Siegel, Ryan Harrison and Liam Wallington also chipped in for Costa Mesa, which has outscored its last two foes, 21-7, after incurring a 5-0 opening-game loss to Ocean View.
"I think they were nervous that first game," Wood said. "The last couple days, they've been playing loose, goofing off and talking."
Wood said Mazur settled down after some early control problems and he credited Letterman for closing the deal to allow Rodriguez and Brown to remain fresh for tonight's contest.
"His pattern is to struggle early," Wood said of Mazur. "After we get him going, he's pretty good."
Wood said shifting Palma from second base to shortstop after the first game has helped solidify the defense.
"Matty's a stud at shortstop," Wood said. "And you know what's cool about him? He takes control. He's talking to the other guys in the infield."
Six Fountain Valley errors led to four unearned runs, while Costa Mesa made just two defensive miscues, yielding one unearned run.