Perhaps Illinois State's home dominance and playoff experience will be more decisive factors as the No. 2 seed tries to advance to the quarterfinals for the second consecutive year Saturday against their upset-minded Missouri Valley Conference rivals.
The Leathernecks led by a touchdown midway through the third quarter at Hancock Stadium on Oct. 24 before Illinois State (9-2) scored 27 unanswered in a 48-28 win.
Marshaun Coprich ran all over Western (7-5) for 206 yards and two touchdowns, while quarterback Tre Roberson added 89 rushing yards and two more scores. Anthony Warrum finished with four catches for 170 yards and two touchdowns.
"It was interesting when the bracket came out that (the MVC teams are) all going to play each other at some point," said Spack, who has guided ISU to back-to-back MVC titles. "We know (Western) pretty well but I think there will be little differences in this game."
Coming off a first-round bye, Coprich will try to keep putting up eye-popping numbers. He totaled 505 yards on 8.6 per carry and seven scores in the last two games.
Coprich, a FCS Offensive Player of the Year nominee, became only the fourth player to earn MVC Offensive Player of the Year honors in back-to-back seasons after ranking second nationally with 1,710 rushing yards and tying for second with 20 touchdowns.
Roberson leads the nation with 20.6 passing yards per completion, while Warrum rounds out the big three with an FCS-high 24.0 yards per reception and 13 touchdowns.
The Redbirds have won an FCS-best 18 in a row at home and haven't lost to the Leathernecks there since 2007, but Spack cautions that things could be different this time.
"I think the team that lost (the first meeting) has a little bit of the advantage, but you kind of throw all that stuff out the window when you line up and play," he said. "We have to prepare for what they do well and their staple plays as I'm sure they will do with us. We can't worry about what happened last time other than maybe the things that hurt you."
Trenton Norvell and Lance Lenoir both did a little of that for the Leathernecks. Norvell completed 27-of-47 passes for 313 yards and two touchdowns against the Redbirds, but he hasn't played since undergoing an appendectomy in early November.
Norvell might be able to return this weekend, though Sean McGuire has guided Western to three consecutive victories after a 4-5 start. The freshman has thrown for an average of 265.7 yards with four touchdowns and five interceptions in the last three.
"He's very good in the quick game and can throw the ball down the field," Spack said. "He can move and he's tough to tackle because he's a strong guy."
Lenoir is likely to be the primary target in the passing game after finishing with season highs 11 catches for 131 yards and a touchdown at Hancock Stadium. He's totaled 30 receptions for 431 yards and five scores in three career games versus Illinois State.
The Leathernecks may want to establish a ground attack behind Nikko Watson. The senior workhorse has rushed 92 times for 483 yards and five touchdowns during the winning streak, though the Redbirds limited him to 53 yards on 18 attempts in October.
Western, making its first playoff appearance since 2010, will have to play as well defensively as it did on the road last Saturday. The Leathernecks forced four turnovers and held Dayton to a season-low 206 total yards in a 24-7 first-round victory. Redshirt freshman Pete Swenson led the effort with four sacks.
This will be the 98th meeting in an all-time series that dates back to 1904.