By Phil Perry, Globe Correspondent

FOXBOROUGH – A full-fledged party took place on the Gillette Stadium concourse as Leominster celebrated its 21-6 Central Mass. Division 1 Super Bowl win over St. John’s of Shrewsbury today.

Blue Devils fans left their seats to mob the Leominster players before and after the trophy celebration. Their full-throated cheers were unrelenting.

The championship, Leominster’s 11th, would have been celebration-worthy under any circumstances. But the extent to which Leominster improved en route to its title made the occasion even sweeter.

Under first-year coach David Palazzi, the Blue Devils started the year 0-3 before winning 10 in a row to end the season.

“It's a great feeling,” said Palazzi. “I'm just overjoyed for the kids. The amount of work that they put into it, the change that went on, the difficult start, (they were) just really focusing on what they need to do to be successful. To start 0-3 with a new coach, to overcome that . . . My assistant coaches, hats off to them and the seniors and the rest of the team for really pulling it together.”

The Super Bowl started as slow Leominster's season. St. John’s received the opening kick and went 74 yards in 13 plays, but on fourth down from the Leominster two-yard-line, Leominster sophomore safety Neil O’Connor tackled St. John's junior running back Shadrach Abrokwah in the backfield to give Leominster possession.

"When it came down to it, we were tough. We got the job done and kept them out of the end zone. We let our offense get a chance to start fresh,” O'Connor said.

Later in the first quarter O’Connor and his older brother, senior Kevin O’Connor, connected to give Leominster a 6-0 lead. It was a trick play that the O’Connor brothers said they worked on all week. Quarterback Garrett DelleChiaie passed to Neil behind the line of scrimmage, and Neil turned and fired downfield to his wide-open older brother for a 44-yard touchdown.

“To tell you the truth, that's the best we ran it,” Kevin said.

On the first play of the second quarter, it was Kevin’s turn to thwart a St. John’s drive. O’Connor intercepted St. John’s quarterback Connor Kurtz at the Leominster five-yard line, setting up the Blue Devils for a 19-play, 95-yard drive that lasted almost the entire second quarter (9:45). DelleChiaie capped the drive with a 4-yard touchdown pass to senior tight end Daniel Curley.

In the third quarter, St. John’s stopped itself when Kurtz had to fall on a bad snap on fourth-and-goal from the Leominster two yard line.

“We had our opportunities,” said St. John’s coach John Andreoli. “We were inside the 10 yard line I think three times. We let them out on third down a couple of times. They converted on third down several times on us. So those are the difference in the game.”

Leominster senior running back Geraldo Rivera scored from 14 yards away with 1:42 left in the third quarter to give the Blue Devils a 21-0 lead. A 17-yard touchdown reception by Pioneers senior receiver Efrain Montalvo cut the lead to 21-6 early in the fourth quarter.