LIVERMORE FALLS – Going into Thursday’s Western Class C quarterfinal, Livermore Falls was worried that Winthrop had seen too much of starting pitcher Derek Castonguay over the past year.

The Ramblers would probably agree that they’ve seen more than enough of him, too.

Castonguay beat No. 5 Winthrop for the third time in a year with a four-hit complete game and sent the fourth-seeded Andies to the semifinals with a 7-1 win.

Livermore Falls will face St. Dom’s, the team it beat in last year’s regional final, at noon on Saturday in Auburn.

Catcher Willie Brown had three hits and Josh Tainter two to lead the Andies (14-4). Winthrop finished at 12-4.

“We do have a lot of confidence, but we’re still a pretty young squad,” said Castonguay, a junior who beat the Ramblers, 10-3, in last year’s semifinals and 13-6 during the regular season. “We still need to focus on the next game and not the game after that.”

Castonguay (four Ks, three walks, one hit batter) wasn’t overpowering, but he didn’t need to be after his offense spotted him six runs in the first inning.

“We got some runs early and took a little pressure off early,” Livermore Falls coach Brian Dube said. “This is the third time Derek’s faced them and sometimes that familiarity is a problem. But he changed speeds well.”

Caleb Baron gave Castonguay all the support he would need with a two-run home run to the opposite field two batters into the bottom of the first. The Andies continued to rough up Winthrop starter Ryan Conant, who was pressed into duty with injuries to Easton Morang and Jake Steele.

The Andies ended up sending 11 men to the plate and Conant didn’t survive the inning. Tainter and Ryan Jackson clubbed back-to-back RBI ground-rule doubles to make it 4-0, then a walk, and errant pickoff throw and a wild pitch upped the lead to 6-0.

“We were in a bit of a bind,” Winthrop coach Marc Fortin said. “We had scheduled Easton to start. He had a collision (Wednesday) with our center fielder and had a pretty bad charley horse and was unavailable today. Ryan’s a sophomore and unfortunately had a bad inning.”

Tyler Reeve relieved Conant with two out in the first and stopped the bleeding. The freshman held the Andies to just one more unearned run the rest of the way.

Reeve did his job, and even drove in the Ramblers’ only run in the second to try to ignite a rally. But Castonguay didn’t give the Ramblers (12-4) any more than a glimmer of hope for a comeback.

“Last time out against Hall-Dale, he gave up seven two-strike singles,” Dube said. “So I talked to him and Willie about better location when he was ahead in the count, not giving them a hitter’s pitch but a pitcher’s pitch, and I thought he did well with that today.”

“I just tried to change speeds a lot and keep them guessing the whole game,” Castonguay said. “I was very proud of our defense. I actually gave our third baseman a lot of work today.”

Winthrop’s biggest threat after the second came in the fifth, when a hit batter and a single gave Winthrop two men on with none out. But Castonguay got Morang to hit a grounder to third at Jackson, who tagged the bag, then threw a one-hopper to first that Tainter made a nice snag on, for the double play that snuffed any chance of a big inning.

“That’s the best we’ve played defensively all year,” Dube said. “Jackson had a great game at third. All the way around, we played solid defense.”