Both of their remaining schedules are also filled with teams with postseason aspirations.
A Halloween showdown between the 17th-ranked Grizzlies and No. 12 Vikings begins a scary final stretch for each team which could make or break their postseason hopes.
As expected at the season's onset, the Big Sky is one of the FCS' deepest conferences. Montana State is tied for sixth in the league but is ranked No. 19 in the STATS FCS Top 25, while Southern Utah - undefeated in conference play - is the first team outside the rankings. The Thunderbirds also catch a bit of a break in their quest to reach the playoffs by not having to face fifth-ranked Eastern Washington or Montana.
Neither the schedule for Portland State nor Montana is as forgiving.
The Vikings (6-1, 3-1) begin their daunting stretch at home against the Grizzlies (4-3, 3-1), whom they've lost to eight straight times. Up next, they visit Northern Colorado and then face the conference's lone unbeatens - hosting Southern Utah before concluding the season at Eastern Washington.
Montana's final slate may even be more intimidating.
After visiting Portland State, the Grizzlies play at Idaho State, host Eastern Washington and finish up at Montana State in the Brawl of the Wild.
"On paper it's very difficult," first-year Montana coach Bob Stitt said of the schedule. " ... We've got some great teams coming up but you just prepare each week to try to beat that team. If you try to look at we've got to beat these four teams to win it that's a tall task. We just got to chip away at it."
Seemingly making things tougher for the Grizzlies is they're down to their No. 3 quarterback after injuries to Brady Gustafson and Chad Chalich. However, sophomore Makena Simis proved in his first career start that he's plenty capable of carrying the reigns of Montana's air-it-out offense, matching a school record with six touchdown passes while throwing for 321 yards in last Saturday's 42-16 win over North Dakota.
Gustafson is close to returning but Simis will get another shot for Montana, which is seventh in the FCS with 312.0 passing yards per game.
Portland State opts to move the ball on the ground, ranking second in the Big Sky in rushing at 258.4 yards per game. Senior David Jones has a team-high 638 run yards and averages 8.2 per attempt - fourth-best in the FCS among those with at least 75 carries.
A stout defense has also played a big role in the Vikings' success. Portland State is second in the league with 349.6 yards allowed per game and is tied with Southern Utah with an FCS-best plus-12 turnover margin.
A look at the other Week 9 games Saturday in the Big Sky (all times Eastern):
MONTANA STATE AT NORTH DAKOTA, 2 p.m.=
Montana State (4-3, 2-2) was picked to win the Big Sky in the preseason coaches' poll, but finds itself facing a bit of an uphill climb. It is 0-3 on the road with Big Sky losses to Portland State and Northern Arizona - and fell to Eastern Washington in what was considered a nonconference game - and still has dates with Southern Utah and Montana.
"Our backs are against the wall," junior running back Chad Newell told the school's official website after last Saturday's 63-7 win over East Tennessee State. "Straight up, that's how it is. We have to win football games."
After blowing out a first-year FCS program last week, Montana State's high-powered offense is in for a tougher test against a North Dakota team that has the FCS' fifth-best rush defense, allowing an average of 82.4 yards.
The Bobcats are third in the Big Sky in rushing at 223.9 yards per game and sixth in the FCS in passing at 315.7. Dakota Prukop has passed for 18 touchdowns and run for another eight for Montana State, third in the FCS in scoring at 45.9 points.
North Dakota (4-4, 2-3) will have a tough time keeping up the with Bobcats, as its 326.9 yards per game ranks last in the Big Sky and it's averaging 23.7 points during a three-game losing streak.
WEBER STATE AT EASTERN WASHINGTON, 3:05 p.m.=
Every week opposing teams game plan on how to contain Eastern Washington's Cooper Kupp, and every week the star wide receiver puts up eye-popping numbers. Kupp was named the STATS Offensive Player of the Week after registering school records of 20 receptions and 275 yards in last Saturday's 43-41 win over Northern Colorado.
He also had three more TD receptions to pass three more on the career list - including Jerry Rice - bringing his career total to 52. The junior ranks second in FCS history and is six away from New Hampshire's David Ball's record set from 2003-06.
Led by Kupp and quarterback Jordan West, the Eagles average an FCS-best 409.1 passing yards. They're also third in total yards at 547.3 and seventh in scoring at 41.4 points.
"You have your hands full stopping Cooper, but they got to have an O-line to protect for them, which they're very good at, and their quarterback does a great job of getting the ball out of his hands," Weber State coach Jay Hill said. "When they're hitting on all cylinders they're probably as good as there is in the country."
Eastern Washington (5-2, 4-0) is closing in on its sixth playoff berth in seven years and has won 18 straight regular-season home games, but coach Beau Baldwin is wary of upset-minded Weber State.
"Weber State doesn't care about what our record has been in the past and what our home record is," he said. "They are going to be excited to come up here, like they should be."
The Wildcats (4-4, 3-2) won at Montana in Week 6 and have already doubled last season's win total. They'll look to take advantage of facing an Eastern Washington team that ranks 122nd out of 125 FCS schools in defense, allowing an average of 511.1 yards.
CAL POLY AT SOUTHERN UTAH, 5 p.m.=
Southern Utah (5-2, 4-0) is tied atop the conference but still has some work to do to reach the playoffs for a second time in three years. It opens its November schedule with road games against Montana State and Portland State, which means getting a win against Cal Poly (2-5, 1-3) is paramount.
The Thunderbirds' formidable defense will be tested by the Mustangs, who lead the FCS in rushing yards at 391.7 per game. Quarterback Chris Brown has a team-best 702 run yards with running backs Joe Protheroe (629) and Kori Garcia (586) not far behind.
Brown and Garcia each had fourth-quarter touchdown runs and Cal Poly amassed 452 rushing yards in last season's 42-39 home win over the Thunderbirds.
"It's really about formations and assignments and making sure that our guys are on point," Southern Utah coach Ed Lamb said about defending the triple-option.
Southern Utah has the Big Sky's second-best rush defense, yielding 126.0 yards per game, and is fourth in the FCS in scoring defense, surrendering 11.9 points per game.
NORTHERN COLORADO AT NORTHERN ARIZONA, 5 p.m.=
Northern Arizona (4-3, 2-2) is finding success behind freshman Case Cookus, who has an FCS-best 187.3 passer rating. He is averaging 287.3 passing yards with 11 TDs to one interception in his last three games, which includes a victory over Montana State.
He'll look to pick apart Northern Colorado (4-3, 2-3), which has allowed an average of 319.0 passing yards in its last three games.