Mike Riley's first season at Nebraska has already become a stress test.

After the Cornhuskers erased a 23-point fourth-quarter deficit to force overtime against Miami, only to lose 36-33, Riley joked that he might have to start working out again to strengthen his 62-year-old heart.

No one reasonably expected Nebraska to win a Big Ten championship this year, but the Huskers' first 1-2 start since 1981 is causing mild anxiety among a fan base unaccustomed to losing twice in September.

More from FoxSports

Nebraska opened with a loss at home to BYU on a Hail Mary, built some confidence with an easy win over South Alabama and then overcame a long string of mistakes to force overtime against Miami before self-destructing at the end. Nebraska finishes nonconference play at home this week against Southern Mississippi (2-1).

Riley pointed out to his players in the locker room they are less than a minute away from being 3-0. That doesn't change the fact this is only the second time since 1960 the Huskers have lost two of their first three.

''You can't help but appreciate what happened in the second half,'' Riley said after Saturday's game. ''But there's always going to be something that gnaws at you because you know it doesn't have to be this way.''

There's lots of room for improvement.

Using a hybrid of the previous staff's spread offense and the pro-style system Riley prefers, the Huskers lead the nation with 70 plays of 10 yards or longer, and Tommy Armstrong Jr. is throwing for 299 yards a game.

But three of his five interceptions came against Miami, including a bad one in overtime that helped set up the Hurricanes' winning field goal.

The Huskers also had seven dropped passes and were penalized twice for having 12 men on the field and twice for illegal formations.

''High school and middle school mistakes,'' Armstrong said.

Defensively, the Huskers have given up 13 plays of 30 yards or longer through three games. Only UTEP and SMU have allowed more. Nebraska is surrendering 357 yards a game through the air, the most by any team other than Indiana. Nebraska also is the fourth-most penalized team in the nation at 10.3 a game.

Offensive lineman Alex Lewis was flagged three times against Miami. The most egregious was an unsportsmanlike conduct penalty in overtime after he shoved Corn Elder when he was out of bounds after intercepting Armstrong. That penalty let Miami start its overtime drive from the 12-yard line instead of the 25.

Lewis, a team captain, took to social media early Sunday to blast fans who blamed him for the loss.

He wrote on Facebook that he's going to prove to himself and his family that he's ''better than these fair-weather fans.'' He added: ''You will kiss my feet when im done with you! So screw everyone who ever doubts me.''

The tweet linking to his Facebook post was deleted by late morning.