One team enters high school football's regional semifinals on a three-game winning streak; the other, having dropped two straight in resounding fashion.

Either way, Winthrop and Mountain Valley both must answer the same nagging question: Has anything really changed since the first time they confronted this weekend's playoff opponent?

Each absorbed a one-sided loss that ended a lengthy winning streak and signaled a seismic shift of power in the Campbell Conference.

Winthrop hadn't lost a regular-season game since 2006 — a run of 19 games — when it hosted Dirigo in Week 2. The Cougars were challenged for a half before storming to a 34-8 victory that built the foundation for an undefeated regular season.

Mountain Valley wielded its own 19-game winning streak after a 7-0 start. It ended with a screeching halt when York scored the first 20 points of the game and rolled, 33-14, two weeks ago in Rumford.

York will host the Western Class B rematch at 7 p.m. tonight, with Dirigo rolling out the red carpet for the Western Class C semifinal at 1 p.m. Saturday.

Here's a closer look at the matchups:

#3-Mtn. Valley (7-2) at #2-York (8-1)

York clinched home-field advantage for the encore by rallying past rival Wells a week ago. The Wildcats pounded out that win largely without the help of senior tailback Jared Prugar, who suffered a hamstring injury just prior to the game and saw only limited duty.

Prugar riddled the Falcons for 36 carries, 227 yards and three touchdowns a week earlier, topping 200 yards in the first half.

"They punched us in the face, and we never answered," said Mountain Valley coach Jim Aylward.

Brad Stephens proved his capability to handle the load for York in Prugar's absence last week. Fullback Jack Radke and a veteran line also are key to York's prosperity.

A few aches and pains for the home team might merely level the playing field for the Falcons, whose Class B title defensehas been riddled with injuries.

The latest blow was delivered in last week's 34-0 loss at Cape Elizabeth. Junior quarterback and defensive back Cam Kaubris, who missed the first five games with a separated throwing shoulder, was reinjured and is out for whatever remains of football season.

Chris Day has filled in capably for Kaubris. The Falcons will rely heavily upon the running of Matt Duka to carry their upset hopes.

Duka, Cole Clark, Ryan Laubauskas, Nick Taylor and Christian Durland are the leaders of a Mountain Valley defense that has posted five shutouts.

#4-Winthrop at #1-Dirigo

There aren't many apparent dents in the Dirigo armor this season, but the Cougars have been plagued by the occasional slow start.

Last week's quarterfinal win over Maranacook was a tenuous 7-0 contest until late in the second quarter, when a lengthy touchdown drive and a defensive stop on downs in Black Bears territory completely flip-flopped momentum.

Dirigo suddenly exploded to a 35-0 lead at the half and breezed to a 42-8 win.

"We scored 21 points in a minute-seven," said Dirigo coach Doug Gilbert. "Just to come up with three scores that quickly was amazing for those guys."

Spencer Ross scored touchdowns receiving, running back a punt and returning an interception. Fullback Tyler Chiasson and quarterback Nic Crutchfield keyed the Cougars' ground game. Crutchfield fired TD strikes to Ross and Alex Miele.

In addition to Maranacook, regular-season contests against Oak Hill, Madison and Winthrop were closer than expected for Dirigo at the half.

Winthrop was tied at 8 until late in the second quarter and turned in a goal-line stand in the closing seconds of the first half to keep the Cougars within a manageable 15-8.

The Ramblers lost two-way starters Ryan Conant, Eric Duplessis and Robin Cook to injury in that game. Conant's work in the backfield has been crucial to Winthrop's current three-game winning streak, capped by 7-0 and 14-12 wins over Lisbon.

Conant scored the lone Winthrop TD against Dirigo out of the Ramblers' productive Wildcat formation.

Ross reached the end zone on three of his seven carries in the first encounter. Crutchfield and Miele connected for a long score through the air on Dirigo's first series.

"It's somebody that we know," Gilbert said of Winthrop, the defending conference champions.

koakes@sunjournal.com