Abdullah, the nation's leading rusher in 2013 with 1,690 yards, picked up where he left off in Nebraska's season-opening 55-7 home win over Florida Atlantic last Saturday.
The senior piled up a career-high 232 yards, including a 47-yard touchdown run, before leaving for good in the third quarter. He became the school's eighth player to go over 3,000 rushing yards in a career.
"He's the best back in the nation," Armstrong Jr. said of Abdullah, who has averaged 145.7 yards on the ground over his last 10 games. "I think (some analysts) have him the No. 2 or 3 back in the Big Ten. I think he's taken that to heart and proven to everyone why he should be one of the contenders for the No. 1 spot."
Armstrong Jr. threw for a career-best 271 yards and two touchdowns before he sat down late in the third. The sophomore quarterback added 62 yards rushing and another score on his seven carries.
Jordan Westerkamp had seven catches for 125 yards and became an instant social-media sensation when he put his hands behind his back to snag a tipped pass along the sideline. Westerkamp also had the winning grab on a 49-yard Hail Mary as time expired against Northwestern last November.
The Cornhuskers (1-0) rushed for 498 of their 784 total yards, which was the fifth highest total in program history and their most since putting up 787 in 1991.
"I know what this offense has the potential to do, but let's not get ahead of ourselves now," coach Bo Pelini said. "Our captains said we didn't come into this season to beat Florida Atlantic. So we won a game we should have won."
Despite the team's tremendous offensive success, the Cornhuskers suffered a big loss defensively with Gregory unlikely to play after leaving Saturday's first series with a knee injury.
Gregory, who led the Big Ten with 10.5 sacks last season, underwent a procedure to remove scar tissue Sunday, leaving junior Jack Gangwish in line to start at defensive end against McNeese.
Pelini said Gregory had a basketball injury from several years ago "flare up" in his knee. While Gregory probably could play this weekend, Pelini said it's more likely he won't return until Sept. 13 at Fresno State.
"We're not looking to rush him back right now," the coach said. "Make sure he's 100 percent, feels good, and when that time frame is, we'll see."
The Cowboys, considered one of the nation's top FCS teams, haven't announced a starting quarterback for their season opener, but juniors Will Briscoe and Tyler Bolfing are likely to get the majority of the snaps.
McNeese, however, will be without one of its top receivers, Wes Briscoe, who is expected to miss the season because of a knee injury. The senior also missed most of 2013 when he injured his other knee in the fourth game.
Sophomore Damon Gladney could be an option after he was given a clean bill of health even though he was originally expected to miss at least the first three games due to injury.
The Cowboys averaged 40.0 points in 2013, finishing 10-3 for their ninth straight winning season. They last played a ranked FBS opponent in 2010, losing 32-10 at then-No. 9 LSU.
"It's a great opportunity for our program," coach Matt Viator said. "It's obviously a huge challenge."
Nebraska beat McNeese 38-14 in October 2002 in the only previous meeting between the schools. The Cornhuskers have won 16 straight versus unranked, nonconference opponents since September 2008.