RICHMOND — When the Northeastern men’s basketball team earned its first trip to the Colonial Athletic Association tournament championship game, rallying from a 24-point first-half deficit in an improbable semifinal victory over George Mason, coach Bill Coen cautioned his top-seeded Huskies still had much work to do.

“The job is only half done,’’ Coen said, referring to his team’s quest for its first NCAA Tournament berth since 1991.

In the last CAA tournament to be staged at Richmond Coliseum, the top-seeded Huskies (20-12) departed with some unfinished business Monday night after getting run out of the building in a 70-57 beatdown against third-seeded James Madison (20-14).

Unlike their stirring victory Sunday, NU was unable to come all the way back after the Dukes led by as many as 22 in the first half. Against George Mason, the Huskies staged the largest comeback in the 93-year history of the program.

Jonathan Lee led the Huskies with 14 points and A.J. Davis led James Madison with 26 points, propelling the Dukes to their first CAA tourney title and NCAA Tournament appearance since 1994.

Coen said the limited tournament field, which was at seven teams without anchor teams Virginia Commonwealth (now in the Atlantic 10) and Old Dominion (ineligible after declaring its intention to leave for Conference USA), would likely produce “a neutral tournament.’’

But any neutrality went out the door when James Madison imported eight busloads of purple-clad fans from its campus in Harrisonburg, Va.

The partisan crowd made its presence felt as the Dukes stormed to a 22-6 lead. JMU broke a 5-5 tie by reeling off 15 straight points, before Demetrius Pollard snapped NU’s 6-minute-19-second scoring drought by hitting a free throw to make it 20-6.

After hitting two field goals in the first 1:38, including a game-opening trey by Joel Smith, NU missed its next 11 shots while committing four turnovers. That opened the door for the Dukes to streak to a lead that grew to 24-6 on Rayshawn Goins’s strong low-post move with 9:03 left in the half.

It was precisely the kind of start NU had hoped to avoid for a second straight day.

JMU twice extended its lead to 20 (26-6 and 28-8). When Marco Banegas-Flores finally got a basket to drop, on a foul-inducing lane penetration with 5:29 to go, it marked NU’s first field goal in 13:07.

Banegas-Flores made the accompanying free throw to cut JMU’s lead to 28-11.

The Huskies waged a monumental struggle to find the basket. NU shot 5 for 24 in the first half.

Davey Walker scored on a layup with 3:49 left in the half and Smith drained a trey from the top of the key that pulled NU to 37-18 with 1:16 to go.

But the Dukes, who hit 14 of 25 field goals in the first half, went on to control a commanding 40-18 lead at the break after getting 17 points from Davis, their senior guard.

When the teams returned to the floor for the second half, one JMU fan hollered a backhanded compliment at NU during warm-ups: “C’mon Huskies, you beat A.J. Davis by 1 in the first!’’

After he went 0 for 3 in 16 scoreless minutes in the first half, Lee scored all 10 of NU’s points in the first 6:04 of the second half, pulling the Huskies to 45-28.

Reggie Spencer drew contact on his layup in an attempt to answer a 3-pointer by Davis, but missed the foul shot, enabling JMU to maintain a 48-30 lead. Pollard then converted on a strong lane cut to cut it to 49-32.

The Huskies continued to whittle away when Lee scored on a driving layup, making it 49-34 with 10:57 to go. After Davis scored on a high-flying alley-oop, NU scored 9 straight points to pull to 51-43 with 8:20 left.

Walker gave the Huskies a spark with his foul-inducing breakaway layup that made it 51-39. He followed with a half-court steal that led to Lee’s stop-and-pop jumper that pulled the Huskies to 51-41, and that prompted JMU coach Matt Brady to signal for a timeout with 9:03 left.

NU cut the deficit to 51-43 on Derrico Peck’s putback with 8:20 to go, but the Huskies’ hard work went for naught when Smith fouled out with 7:46 to go, putting Andre Nation on the line for three foul shots.