San Mateo American keeps rolling

While the American roster is built on pitching — Wednesday’s starter Jagger O’Brien was his usual, masterful self — the boys from San Mateo got a power surge from left-handed slugger Pono Rosenberg, who clobbered a three-run home run in the fourth inning to help put a 7-1 victory over Hillsborough at Middlefield Ballpark on ice.

“He’s been struggling putting the ball in play, and he’s a little feast or famine,” San Mateo American manager Jason Gordon said of Rosenberg, who is now 2 for 5 with two strikeouts in the tournament. “But ... he’s the strongest kid I’ve ever seen. He just has to put the bat on it. ... If he gets the ball in the air, it’s leaving the yard.”

Prior to the offense waking up, however, O’Brien again took the team on his broad shoulders. American has played two games in the D52 tournament, and the big right-hander has started them both. He left Sunday’s 1-0 win over Belmont-Redwood Shores in the fifth inning with a no-hitter intact, and held Hillsborough hitless for 3 2/3 innings Wednesday.

All told, O’Brien opened the tournament with 8 1/3 hitless innings.

“He threw really well,” American catcher Matthew Ward said. “I mean, they couldn’t touch him at all, really. ... At times he was a little wild but I felt he did a good job of calming down and throwing strikes, and I felt he kind of kept us in the game because our bats weren’t awake at the start.”

Hillsborough No. 5 hitter Kenny Stroud broke up the hitless streak with a two-out single in the fourth, driving home Will Glaser with the team’s only run of the game. Stroud stood in there against an effectively wild O’Brien — who walked four and hit one batter — got knew what to do with a 1-1 fastball, knocking it right back through the middle, making O’Brien dance out of the way of the high-exit-velocity heat seeker.

“Just really proud of Kenny,” Hillsborough manager Tony Guglielmi said. “There was two outs and I thought maybe that would have sparked a little two-our rally. It didn’t, and they came back and scored a few runs in the next inning. But that was a real big at-bat for Kenny, and for all the other guys seeing that. Hopefully they take that going forward. Because we’re going to need to play Friday, Saturday and Sunday now. We’ve got to keep it going.”

The hit knocked O’Brien out of the game, as American turned to Ward in relief. Ward promptly retired the side with three straight strikes, fielding the third one on an inning-ending comebacker. The right-hander closed out the win by breezing through 2 1/3 perfect innings of work, striking out four.

Ward and O’Brien combined for 13 strikeouts overall.

“He’s a great guy to pitch with a lead because he’s going to fill the zone up and get you out of there quick,” Jason Gordon said.

American got on the board quickly in the first. Connor Workman led off with a walk, then motored around to third on a wild pitch and a stolen base. Hudson Wong then shot a single to center to knock home Workman, staking American to a 1-0 lead.

Wong was 2 for 2 with two RBIs on the night, but Jason Gordon said his first-inning single was the team’s biggest swing of the bat of the game.

“That was big,” Jason Gordon said. “Relax a little bit, play with a lead. Even though we knew we were dealing with a stud (opposing pitcher) over there. We knew he was going to put some zeroes up. ... We like to play small ball with [Wong], and he’s a great team player and he’ll put bunts down. But he can hit. The kid is a solid hitter. He’s in the 2-hole for a reason.”

In the third, Ryan Derossett led off with a double that Hillsborough nearly turned into a diving play in center, but the ball kicked off the fielder’s glove and rolled away, allowing Derossett to hustle into second. After a wild pitch moved him to third, Derossett got thrown out at the plate on a gutsy play by relief pitcher Carson Brayton, who wrestled a swinging bunt off the bat of Christopher Moreno and fired home for left-hander catcher Luke Damelio to slap down the tag across his body for he out.

“He probably knew he didn’t have a play at first, and he was like: ‘I’d better get this guy going home,’” Tony Guglielmi said. “So, he went home. They’ve been making great plays through three weeks of practices, and he’s just absolutely knows what to do with that ball when he gets it.”

The American offense kept its foot on the pedal though. Cody Gordon followed with a bunt single, and Carter Weyer flipped a single to right to load the bases. Workman and Wong each produced RBIs without the ball leaving the infield, to up American’s lead to 3-0.

Then in the fifth, American broke it open.

“We needed to break out in a big way,” Jason Gordon said.

Ward led off the inning by getting hit by a pitch in the helmet. Everyone in the park seemed concerned except for Ward, who tried to immediately run to first base until home plate umpire Andy Fest stopped him for a health check. Ward stayed in the game, and Milo Werner followed with a sharp single to right to set the table for Rosenberg.

The big left-handed slugger delivered with a towering, opposite-field home run.

“It was a high pitch and it was fast, and I just kept my hands on top of it and drove it to the opposite field,” Rosenberg said. “... I ran just in case because it was a line drive, but I felt it off the bat pretty good.”

Rosenberg’s three-run bomb knocked Hillsborough starting pitcher Jeremy Pak out of the game. Like O’Brien, Pak was starting his second straight game of the tournament with two days’ rest between pitching appearances, and his staying under 50 pitches in Hillsborough’s 5-4 win over Pacifica in Sunday’s opener.

“I think he threw absolutely beautiful,” Tony Guglielmi said. “As we’ve been saying all year throughout our practices, he’s an athlete, he’s a stud, and he’s a total competitor.”

American scratched out one more run in the fifth with singles from Maddox Stone and Moreno, before Cody Gordon lofted a popup behind third base that glanced off the shortstop’s glove right on the line for an RBI single.

Ward bounced back from getting hit in the head by striking out the side in the fifth.

“It didn’t hurt that much because it was a curveball,” Ward said. “But there was still a ringing in my ear. I had a little headache after that but when I started pitching again it went away.”

American now advances to face Alpine in the winners’ bracket semifinals Saturday at 4 p.m. Alpine advanced Wednesday with an 8-2 win over Menlo-Atherton.

Hillsborough falls to the elimination bracket, and will play Friday at 4 p.m. against the winner of Thursday’s elimination game between Palo Alto and Redwood City.