A young, little-known political upstart and first-time candidate scored a stunning upset last night by unseating 18-year incumbent John Tierney in the Sixth Congressional District.

Thirty-five-year old Seth Moulton accepted the Democratic nomination in a low-key, retro VFW hall in Salem after a potluck dinner with high-energy supporters.

"I don’t need to tell you that few people outside this room thought I could win,” Moulton told the crowd.

Moulton, an Iraq War veteran and Harvard University graduate, won with 49.3 percent of all votes, compared to 41.4 percent for Tierney. Describing himself, as he had throughout the primary campaign, as a progressive Democrat who opposed the Iraq war, Moulton previewed his argument against the Republican candidate he will now face: Richard Tisei.

"I look forward to contrasting our vision with that of Richard Tisei’s," he said. "We won’t get fresh thinking and new leadership by sending someone to office who was first elected when I was six years old.”

That theme of bringing in someone new, who thinks differently and will try to shatter gridlock – that’s what supporters like Kevin Perley said drew them to the Moulton camp.

"Honestly, I’ve been a Tierney supporter for quite a while and so it’s a tough change for me," Perley said. "But at the same time, it just goes back to having a new perspective, especially after 18 years, and not being against Tierney but it’s more of a shift toward getting things to change.”

Less than a mile away, the Tierney camp was lodged in a distinctly different setting: the posh, historic Hawthorne Hotel. Supporters sat at candlelit tables and, as in the Moulton camp, few were paying attention to the results on television before Tierney conceded. They expected the night to last much longer, as it did two years ago when Tierney eeked out a win over Tisei.

When 62-year-old Tierney suddenly appeared and began to speak, supporters seemed confused, until they realized it was a concession speech.

“Serving in Congress, representing this district for the last 18 years, has been the greatest privilege and honor of my life," Tierney said.

Tierney’s wife, Patrice, stood to the side with a grim face. Tierney has been dogged by media coverage of her conviction and month-long sentence in federal prison for helping her brother file false tax returns connected with an offshore betting operation.

“I look forward to making sure we have every opportunity to continue in public service one way or another," Tierney said. But essentially, what I want to say here tonight, is how much we love and respect and appreciate everything that you have given. This was just an amazing 18 years, and I appreciate it, and I appreciate you standing with us all the way.”

Some Tierney supporters said he lost because people just wanted someone new. But Jerry Darcy said Tierney could’ve done more to fend Moulton off.

“I think maybe he took the opponent too lightly earlier in the race, and really didn’t come out with any answer to the advertising that was pouring in until really late in the game and might have been too late, you know,” Darcy said.

Darcy said he won’t have trouble supporting Moulton now because he dislikes the other party so much. But other long-time Tierney supporters were more grudging. Elizabeth Toulan of Gloucester said the district had made a bad decision by turning Tierney out.

“He has leadership positions that a freshman congressman will not be able to secure," she said. "He has a team spirit with his colleagues in the Democratic party that you can’t just build overnight. And the district will suffer as a result.”

So what happens now?

"I need some time to think about what happens now,” she said.

Toulan and other Tierney supporters, now adrift, have little more than two months to make up their minds.