WATERVILLE — Two-time defending Eastern A champion Messalonskee limped into this year’s playoffs, losing five of its last eight in the Kennebec Valley Athletic Conference.

As Oxford Hills discovered in Saturday’s regional semifinal, the Eagles are back to their old selves and putting together another deep postseason run.

No. 2 Messalonskee scored three runs in the first inning and pitcher Devin Warren made it stand up with a gritty complete game three-hitter and a 4-2 win over the third-seeded Vikings at Thomas College.

The Eagles (13-5) will try for their third consecutive regional title against top-seeded Bangor on Tuesday at Augusta’s Morton Field. The Vikings end their season at 12-6.

Messalonskee’s 7-2 loss to the Vikings on May 16 was fairly typical of its struggles in the second half of the season, and a paradox of how it played Saturday — pitching, defending and exploiting opportunities to put pressure on the opposition.

The Eagles took advantage of some early jitters for Oxford Hills starter Dalton Rice. They cashed in on two walks and a single that loaded the bases to start the bottom of the first. Jake Dexter’s two-run single and Ben Frazee’s sacrifice fly provided all the runs Warren would ultimately need.

“That was a big confidence-booster for me and the ‘D,'” said Warren, who had one of his two singles in the first and scored the Eagles’ second run. “It keeps everybody in the game that way. You have a little less nerves on you.”

“I think (Rice) was probably over-excited,” Oxford Hills coach Shane Slicer said. “He was up in the zone a little, so that’s what I thought it was. Then he settled in pretty well. I thought he pitched well. But there’s a reason why they’re Eastern Maine champions. They don’t make many mistakes.”

While Rice (6 IP, 6 H, 3 ER, 2 K, 4 BB) found his control and quieted the Eagles’ bats, Warren breezed through the first three innings before his defense helped him escape trouble in the fourth.

First, Jonathan Wilkie made a terrific diving stop on Rice’s bouncer in the hole, jumped to his feet and threw him out at first.

The play looked even more important after Warren walked the next hitter, Nick Attaliades-Ryan. Again, the defense came through as catcher Trevor Gettig gunned him down trying to steal second, rendering Warren’s subsequent walk to Ty Martin meaningless after he got Matt Smith to fly out to right.

“We’ve had not the best defense throughout the season, but since playoffs, we’ve been kicking it into gear. That’s a big help, being on the mound,” Warren said.

Momentum seemed to swing the Vikings’ way in the fifth. They finally got on the scoreboard in the top half, with Riley Chickering’s single plating Brady LaFrance and Matt Beauchesne’s perfect squeeze bunt plating Nick Bowie to make it 3-2.

“I was just trying to aim it too much,” Warren said. “I had the same energy all game. I don’t know what was getting to me. I was just trying to aim it too much.”

“Around the fourth or fifth inning, he looked like he was laboring a little bit and we were debating whether we wanted to take him out. I think he more or less convinced us to keep him in,” Messalonskee coach Ray Bernier said. “He’s a senior and a captain, so he rode with it.”

In the bottom of the frame, Messalonskee loaded the bases on a Jared Cunningham double, Warren single and intentional walk to Zach Mathieu. But Rice battled back to fan Jake Dexter, get Ben Frazee on a fly to shallow left and Jonathan Wilkie on a grounder to short to keep the deficit at one run.

“The fifth inning was outstanding,” Slicer said. “You know, we score a couple. Then they get bases loaded, no out, and we get out of it. We had our chances. We played hard. Warren pitched a great game and defensively they were ready.”

Warren (two strikeouts, four walks) hit Ty Martin in the ankle with a pitch one out into the sixth, but the Eagles promptly turned a 5-4-3 double play to end the inning.

In the seventh, after Messalonskee had added an unearned run to the lead, LaFrance tried to bunt for a base hit, but Gettig pounced on it from behind the plate and threw him out at first.

“They’re pretty sharp defensively,” Slicer said. “We couldn’t get any pressure. We’d try to steal and they’d throw us out. Catcher made a hell of a play in the last inning.”