The Thornton Academy doubles team of Asher Thompson and Jack Cannon knocked off the top seed in the semifinals of the Southwestern Maine Activities Association boys’ tennis doubles tournament on Saturday.

The fourth-seeded duo threatened to pull off one more upset Wednesday in the championship match, but Portland’s Ian McCallum and Sam Mermin overcame a strong challenge to earn a 6-1, 2-6, 6-4 victory at Deering Oaks.

McCallum and Mermin, seeded No. 2, were thrilled to win the league crown after falling in the finals last season.

“It’s awesome … it was sort of our goal all year, and it’s great to accomplish it,” said Mermin.

Thompson and Cannon also had reason to be proud of their performance.

“It was such a great experience. I’ve played in the doubles tournament all four years in high school and each year I’ve gone a little bit farther. It’s such an honor to play in the tournament against such a high quality Portland team,” said Thompson.

“It was great. I was surprised that we got here because we had to face Falmouth in the semifinals, so it was exciting just to get here,” said Cannon.

McCallum and Mermin cruised through the opening set, but Thompson and Cannon controlled the second set.

“We played very good in the first set, and then after we lost the second set, we just gathered and said, ‘OK, they got the best of us and we just need to bounce back, play better tennis than them.’ We went out and we did,” McCallum said.

The third set was tight throughout. Thornton led 3-2, but Mermin and McCallum took four of the last five games to capture the title.

“It was a good match. We played some of our better tennis in the first set and we knew the second set was not going to be as easy as that,” said Mermin. “It was tough to lose (the second set), and I think the third set they started playing great. We were not as clean as we were in the first set and we had to grind it out.”

Thompson was proud of how he and Cannon responded after the lopsided loss in the opening set.

“We just had to persevere like we’ve been doing all season. We knew we were down that first set and we were going to have to win two more,” said Thompson. “Unfortunately, we didn’t get that third set, but we came back and put up a good fight.”

Thornton assistant coach Chris Kohl was impressed with the play of both teams.

“It was great to see (Thompson and Cannon) get here, and that third set was a real high quality set. It’s not a match that they have to go back and say, ‘oh, if I did this or did that.’ It was just a good, quality doubles match,” said Kohl.