Scanlon also got a boost from several endorsements, including those of four city councilors, four School Committee members and Tim Flaherty, who finished third in the preliminary.
"This stuff does get harder as you get older, and I'm getting older," said Scanlon, who is 71. "However, it's not about how many push-ups you can do, it's about helping the city."
As if to emphasize his point, Scanlon leapt off the stage after making his speech.
At the Italian Community Center, Cahill supporters said they were proud of the way their candidate ran his campaign. During one debate, Cahill accused Scanlon of "tearing me down to build himself up," but otherwise made a point of not engaging in negative campaigning.
"Mike Cahill ran the most honorable and upstanding and responsible campaign that one could imagine," Bisson Street resident Charlie Perlo said. "I think we're going to hear plenty from Mike Cahill in the future."
Cahill supporter Dave Battistelli said the attacks on Cahill might have actually hurt Scanlon more than Cahill. But the endorsement of Scanlon of eight elected officials was difficult to overcome.
"Some of the endorsements were surprising and disappointing to our camp," Battistelli said. "We didn't think that was going to happen."
An hour after the loss, a smiling Cahill exchanged handshakes and hugs from his supporters and joked with his nephew, Liam, calling him "my campaign spokesman."
Asked about the sometimes negative tone of the Scanlon campaign, Cahill said, "That's for other people to talk about."
"I feel proud of the way we campaigned from the start," he said. "I am so grateful for my family and my friends and everybody who stepped up to help."
A lawyer who works as executive director of the Alliance of Massachusetts YMCAs, Cahill, 49, was asked if he would run for mayor again.