Just days after announcing an extension for football coach Mike Riley, Nebraska athletic director Shawn Eichorst voiced his frustrations after the Cornhuskers' stunning 21-17 home loss to Northern Illinois on Saturday, saying it was "not acceptable."

"I'm angry, I'm frustrated, I'm disappointed," Eichorst said. "At the end of the day, we have to stay together. It's still early in the season, and we need to find ways to win games like this. I want to continue to show our support, but I also understand there is a lot of frustration out there when you don't win games like today.

"I want to make sure folks understand we've got to get that fixed, and we have to get heading in the right direction, and we have the right coach to do it. But we have to get going."

It was Nebraska's first home loss to a team not in a Power 5 conference or not a major independent since Southern Mississippi won in Lincoln in 2004.

"You go through all those emotions in tough times," Eichorst said. "When you're around these good people and good young men, certainly you think about that and how to lead. It's easy to lead when things are going well. But when you have adversity, you have to stand up and think and do the right things all the time."

Nebraska, which was 3-0 against MAC teams prior to Saturday, was held scoreless in the first half at home for the first time since 2007. In addition to boos, a good number of fans left at halftime and didn't return.

Mike Riley, whose contract was extended through the 2020 season this week, is 16-13 during his tenure with the Cornhuskers. Bruce Thorson/USA TODAY Sports

"We have to prove who we are," said Riley, who was given a one-year extension through 2020 earlier this week. "We've been, I would say, inconsistent at best. That's not even probably accurate. That's been us, and I don't like that."

It is the second time in three seasons under Riley that the Huskers have lost two of their first three games.

Said Nebraska linebacker Luke Gifford: "We are going to keep busting our tails. There is a sense of urgency, and the standard here has not changed."

Information from The Associated Press was used in this report.