WINTHROP — The inaugural season of the Winthrop/Monmouth cooperative football team came to a sudden and dramatic end Friday night in a Western D semifinal game against No. 4 Dirigo.

Senior back Heath Hersom picked up his own fumble and rushed 18 yards for a score with 1 minute, 27 seconds left to play to give the upstart Cougars a 22-20 win against the top-seeded Ramblers (8-1). Dirigo (7-3) advances to next week’s Western Conference final against the winner of today’s game between Lisbon and Oak Hill.

The Ramblers hadn’t had a close game in a month, but appeared emotionally prepared. What they weren’t quite ready for was Dirigo’s wildcat offense which featured direct snaps to its trio of talented backs: Hersom, Tyler Frost and Brett Beauchesne. When the teams met earlier in the season, Winthrop/Monmouth won 24-14.

“The first time we decided to play power football but we didn’t execute well,” Dirigo coach Dave Crutchfield said. “We shot ourselves in the foot tonight a bunch of times but we came out in that wildcat and it worked.”

The Cougars controlled the ball and the clock, running 73 plays to 44 for Winthrop/Monmouth. But the Ramblers took the lead nonetheless with a 52-yard drive highlighted by two fourth-down passes from Jared Hanson to Dakota Carter. Philip Rowe capped the drive with a 6-yard run and Hanson threw a conversion pass to Drew Stratton to make it 20-16 with 8:07 left.

Beauchesne’s long return on the ensuing kickoff gave the Cougars the ball at the W-36, but the Rambler defense held, getting a big third-down hit from Zach Glazier on Frost, a 225-pound bull. They got nowhere on the ensuing series and after a timeout decided to fake a punt on fourth-and-7 from their own 21 and came up 2 yards short.

“At the end we had a chance to run the clock out and I made a call to try to get them to bite on something and it didn’t work,” Winthrop/Monmouth coach Joel Stoneton said. “Those kids should have won that game but I made a bad call and own that.”

Three plays later, Hersom was in the end zone.

“I thought the play was on ‘hike’ and the center snapped it on ‘down,’ ” Hersom said. “I bobbled the snap, I picked it up, I ran left and saw an opening and just put my head down and ran all the way.”

Beauchesne finished with 113 yards on 20 carries, many of those sweeps, while Frost rushed for 97 yards on 19 carries and Hersom 87 on 18 attempts, all with a new offense.

“We put it in Sunday,” Hersom said. “They showed us it on the chalkboard and we practiced it all week long. It was pretty effective.”

The Ramblers scored first, late in the opening period, when Hanson hit Stratton between two defenders and he made a quick cut into the end zone for a 35-yard touchdown reception. Dirigo came back to take an 8-6 lead at the half when Frost threw an option pass to Kaine Hutchins on third-6 from the W-16. Frost rushed the conversion. Winthrop/Monmouth came back in the see-saw battle, scoring on a short drive set up by Stratton’s punt return. Glazier faded into a pile of Dirigo defenders and emerged from the other side to score form 19 yards out. He finished with 41 tough yards on 11 carries.

The Cougars responded with another time-consuming drive of 65 yards, capped by Frost’s 4-yard sweep on fourth down. Hersom rushed the conversion to make it 16-12.

“They had a fantastic game plan,” Stoneton said.”We lost a lot of offensive time because they managed the ball and we couldn’t step up physically and stop that.”

Gary Hawkins — 621-5638ghawkins@centralmaine.comTwitter: @GaryHawkinsKJ