PORTLAND — One thing’s for certain: Later tonight there will be a new Western Maine winner heading to the Class A boys’ basketball championship game March 3.

Top-seeded Deering rode a hot start and a cool, composed finish to hold off Cheverus, the two-time defending regional champion, for a 52-49 victory Friday night in a Western Class A semifinal at the Cumberland County Civic Center.

The Rams (17-3) will play third-seeded Bonny Eagle (17-3) in the regional final at 9 tonight at the Civic Center. The Scots advanced with a 54-39 victory against seventh-ranked South Portland.

Cheverus beat Edward Little for the 2010 state championship, then lost to Bangor in the 2011 final.

The Stags (14-6) entered this year’s regional tournament as the No. 4 seed.

Deering used an aggressive full-court press to build a 10-1 lead, and held the Stags to one field goal in the first quarter — Drew Ferrick’s 3-pointer with 1:35 to play.

“We had to be the aggressor and go after them,” said John Amabile, who had 15 points along to help lead the Rams, along with Thiwat Thiwat’s 16 points.

“We came out hard, they turned over the ball. We built the lead and didn’t want to sit on it, we just wanted to push it the whole game.”

And it worked.

“Absolutely, (our bad start) was them,” said Cheverus Coach Bob Brown. “I didn’t think their press was going to bother us but it did. (Deering Coach Dan LeGage) had his team very well prepared.”

“We knew (Cheverus) had runs in them,” said LeGage. “We made a few adjustments and under tough circumstances, the guys just came through. We’ll enjoy it and get back to work for (tonight).”

The cool finish? Well, 12 of the Rams’ 18 points in the fourth quarter came from the foul line; Deering was 12 of 20 from the line.

None of the Rams were cooler than Cal London, who scored four of his six points in the final 30 seconds to hold off the Stags’ final surge that saw them outscore the Rams 22-18 in the fourth quarter.

“I owed it to the team to come in and do what I do, which is pass the ball and make my foul shots,” London said. “It’s a lot of pressure, I’m not going to kid you. But you just have to focus and get it done.”

The Stags came to life in the second quarter. Shawn Grover (eight points) had two field goals, and Louis DiStasio (19 points) hit both ends of a 1-and-1 and his first field goal of the game with about two minutes to play. Cam Olson (six points) capped a three-point play. The Stags outscored the Rams 11-10 in the quarter, but Deering held a 24-15 lead at the half.

Cheverus kept coming in the third quarter, outscoring the Rams 12-10 to pull within 34-27 entering the fourth.

Then the Stags’ balanced offense, buoyed by DiStasio (8 of 9 from the line), and consecutive 3-pointers by Michael Flaherty and James Kapothansis (nine points) in the final 40 seconds, pulled them within 51-49 before London’s final free throw made it 52-49.

“A number of calls could have gone either way,” Brown said. “They made plays when they needed them, but there’s no doubt in my mind that game could have been ours.