Maine’s Neemias Queta celebrates after his dunk in the third quarter of the a Game 1 win over the Oklahoma City Blue in the NBA G League Finals. Maine hosts Oklahoma City in the deciding Game 3 on Monday night. Derek Davis/Staff Photographer

It didn’t take the Maine Celtics long to move on from a squandered championship opportunity Thursday night.

Before the Celtics were even on their way back to Portland, they were getting ready for their next chance.

Maine will play for its first NBA G League championship at 9 p.m. Monday in Game 3 of the Finals against the Oklahoma City Blue at the Portland Expo. The game will be broadcast on ESPNU.

The Celtics won the series opener, 106-86, then lost Game 2 in Oklahoma City, 99-89. Maine Coach Blaine Mueller wasn’t worried about the loss denting the confidence of a team that had won four in a row and 13 of 15 heading into Thursday.

“I think our guys reset pretty quickly. They understood that we didn’t play well. It happens, it’s part of basketball,” Mueller said. “Everyone was disappointed in the result, disappointed at the outcome of the game, knowing what we could achieve that night and it not happening. But I think the collective consensus … (was) it wasn’t our night. It was theirs.”

As was the case in Game 1, when Maine got out to a 33-14 lead and led by double figures the rest of the way, the first quarter was decisive in Game 2. Maine shot 6 of 24 from the field with six turnovers in the opening quarter, and Oklahoma City grabbed a 25-14 lead.

“OKC knew they were in an elimination game, and we didn’t go out there with the right mindset,” said guard DJ Steward, who scored nine points in the loss. “But I feel like this next game, we’re going to have a way better mindset, knowing it’s a close-out game. … We’re going to go out there, we’re going to play together, play hard, play great defense and just have fun out there.”

While the Blue never found a way back into Game 1, Maine nearly pulled off a comeback in Game 2. The Celtics cut the deficit to four in the third quarter, and then got back within two possessions at 95-89 on Joe Wieskamp’s 3-pointer with 1:48 to go.

A missed 3-pointer by Drew Peterson (29 points) that would have cut the deficit to three turned into a layup for the Blue, essentially ending the comeback bid. The Celtics, though, had done enough to draw some confidence out of the night.

Maine Celtics players Joe Wieskamp, center, and Brandon Slater celebrate a 3-pointer during the Celtics’ 106-86 win over the Oklahoma City Blue in Game 1 of the NBA G League Finals. Derek Davis/Staff Photographer

“We just missed a lot of shots we’re used to making,” said Wieskamp, who scored 13 points. “But I believe in this group, and so does everyone. Everyone believes in each other. We’re continuing to encourage guys to be confident, take open shots, and just go and knock them down tomorrow.”

The Celtics don’t plan to make any significant changes. But they know a fast start is crucial.

“There’s a lot of similarities between the two teams, and really, it boils down to who’s going to be more physical, and who’s going to execute better,” Mueller said. “Which team is going to be more physical (is really) kind of going to set the tone for the game. And can you execute with the other team being really physical, being really aggressive. … You have to be the team that’s setting that tone, and force them to try to match it.”

Helping the Celtics in that pursuit will be the raucous home crowd, which has packed the Expo during the playoffs. It was a sold-out crowd for Game 1, and will be again for Game 3.

“They’ve genuinely been tremendous for us all season long, and especially down this stretch and through this playoff run, where we’ve been fortunate to play a lot at home,” Mueller said. “You want to be playing the elimination game at home, in front of your own fans, because they’ve just been fantastic. Our guys … really feed off that. We’ve seen that and felt that.”

Mueller acknowledged that fans were likely hoping for a chance to see a championship win in person.

“Our guys are excited. We, as a team, wanted to close it out, finish it out and win it,” he said, “but I know our fans are secretly a bit excited to have us come back home, play another home game, and have the opportunity to win it in front of them and with them.”