BEVERLY — The left arm of Gian Gamelli ensured that the Hamilton-Wenham Little League Williamsport all-star team would be playing in the District 15 title game later this week.

Gamelli pitched a masterpiece for Hamilton-Wenham Monday night, spinning a two-hit shutout to pace his squad past Manchester Essex, 4-0, in a battle of unbeaten squads at Harry Ball Field.

The big southpaw threw heat the entire game, striking out 15 of the 20 batters he faced. After punching out the first two M-E hitters in the top of the sixth he walked Caz Ostrowski, and H-W manager Marty Cooke took him out at 65 pitches. It was the only walk he issued all game and came on a 3-2 count.

“Gian carried us on the mound,” said Cooke, whose team automatically advanced to Thursday’s District 15 title game (7:30 p.m. back in Beverly) with the triumph. “What an incredible performance against a very solid Manchester-Essex squad. I was never comfortable until the last batter was out. I know Gian wanted to finish the game, and almost did with that walk coming on a close pitch, but we have to make sure he’s available.

“We’ve been playing well and have to keep it up. We’ll practice and work on the little things to get ready.”

Brae Hurley took over for Gamelli and the first batter he faced, Theo Ostrowski, reached on a throwing error, sending his brother Caz over to third. But the game ended when Theo was caught in a rundown between third and home and he was tagged out by catcher Tyler Russo as he scrambled to get back to the base.

The Hornets only had four baserunners all game. Caz Ostrowski, who pitched, beat out an infield hit in the first inning, but was stranded on base when Gamelli struck out the next two. Drew Cort singled to left field in the fifth with one down, but once again Gamelli whiffed the next two hitters he faced.

“Caz pitched a great game for us,” said M-E manager Matt Ostrowski. “He came out strong and kept their big hitters from doing damage, but that one inning they had a couple of squibs and scored.

“Gamelli was unbelievable; he throws gas every time. He just pounds the strike zone.”

The game was scoreless until the bottom of the third when Galen Clark-Goldfeld ripped the first of his two singles down the left field line, and Hurley was hit by a pitch. Gamelli helped himself with a single up the middle to load the bases, and Clark-Goldfeld came home on James Willett’s fielder’s choice. Russo beat out an infield hit, and a throwing error allowed another run to come home for Hamilton-Wenham.

The eventual victors tacked on an insurance run in the fifth when Gamelli led off with a single, advanced on an errant pickoff throw, and scored on a wild pitch.

Russo did a terrific job behind the plate catching Gamelli. It was lefty against lefty, with the first six batters in the Manchester-Essex lineup all southpaws.

“Russo does a fantastic job,” said Cooke. “My other guys don’t even want to warm Gian up.”

The Hornets will face Danvers American Tuesday (7:30 p.m.) in Beverly for the right to meet Hamilton-Wenham for the district crown. The winner of Tuesday’s game must beat H-W twice to claim the title.