Underwood was out of the locker room with more than seven minutes left until the start of the second half, and he sat alone on the Illini bench.

"Most unusual scene — more than seven minutes left on the halftime clock, and Brad Underwood came back out, sat alone on the bench, Stephen, and just pondered his grease board," Big Ten Network broadcaster Dave Revsine said on Tuesday's BTN broadcast. "I'm not sure I've ever seen anything like that in all my years of covering college basketball. What do you make of it?" 

"I think that Brad Underwood was frustrated with his team's effort — maybe lack of intensity, lack of focus," BTN analyst Stephen Bardo said. "Not to take anything away from the Huskers, because they did an outstanding job in the first half. But Brad Underwood has had to try multiple things with this very talented group, because they are a new group. They have not worked together. So let's see if this technique will work. But I think it's a source of frustration for him, and he's trying to find a different way to motivate his team." 

Illinois led Nebraska 38-37 at halftime.

Illinois went on to defeat Nebraska 72-56.

After the game, Underwood explained his alone time on the bench at halftime. 

"Usually, I wait until about the nine- or 10-minute mark before I go in to give them a little time," Underwood said after the game on Big Ten Network. "I just followed them in. So, I said what I needed to say. It only took about 30 seconds, because we were really, really flat, really emotionless, and if we didn't play with any more energy or mental focus than that, we didn't deserve to win. They got to figure out some of that self on their own. So I just came out, enjoyed a little peace and quiet and enjoyed the crowd."

In the postgame press conference, Underwood gave a similar explanation for spending halftime on the bench instead of in the locker room. 

"I pretty much got everything said in about 30 seconds," Underwood said. "Went to the bathroom, washed my hands, and decided to enjoy the fans and the Orange Krush, look at my play card a little bit, and try to figure out what happened. I wasn't going to sit in there and re-diagram anything up. I pretty much said it in 30 seconds to a minute, and I wasn't really in the mood to listen to my staff at that time. So I just came out and had a few peaceful moments and enjoyed the fans, looked up and saw a lot of orange, and realized how fortunate I am to be a basketball coach at Illinois." 

Illinois guard Ty Rodgers also talked about Underwood leaving the locker room during halftime.

"Yeah, just coach Brad being coach Brad, man," Rodgers said. "He wasn't the nicest guy at that halftime, but yeah, he's great for us. He builds energy into us. Like when he's screaming and stuff, we're not listening to him scream. We're listening to what he's saying. He builds those relationships with each and every one of us, so it makes it way easier."

Illinois, ranked No. 25 in the USA Today Men's Basketball Coaches Poll, improved to 16-6 overall and 7-4 in the Big Ten. Nebraska went to 10-13 overall and 3-9 in the Big Ten. 

Earlier in the season, Illinois won at Nebraska 76-50 on Jan. 10. 

Fred Hoiberg is the Nebraska Cornhuskers men's basketball head coach. 

Erik Hall is the digital sports editor at the St. Louis Post-Dispatch. You can find him on Twitter @HallErik.