Ryan Evans scored a career-high 22 points and the No. 11 Badgers used big runs in the first and second halves to win 64-40 Tuesday night.
"That's a heck of a lesson to take," Sadler said. "They've got a good basketball team and they do it the right way. They don't get in a hurry. Everybody wants to talk about how fast, slow, whatever you play. The fact of the matter is they're efficient."
Sadler said the Huskers seemed to forget what league they are in and reverted to the way they played in the up-tempo Big 12.
He said his players didn't use enough of the shot clock.
"The number of shots we took with 15 or more seconds on the shot clock, if we're going to continue to do that, we're going to continue to get our brains beat out because it's not happening," Sadler said.
"No disrespect, but this league's not going to let you do that. Some of the teams maybe we played in the past, you knew you were going to get enough possessions. You ain't getting possessions in this league, that's one thing I know. You better have some efficiency."
The Huskers shot 31 percent from the field and got to the free-throw line only nine times, making seven.
"We made some shots early, and so I guess we thought we were going to outscore some people," Sadler said. "You better have more shots under 10 seconds than you do over 10 seconds if you're going to win in this league."
The Huskers (8-4, 0-1) had scored the game's first seven points, but Evans' swirling 3-pointer tied it 10-all — and the Badgers (12-2, 1-0) were off on a 19-2 run.
Toney McCray's steal and layup just before the buzzer pulled the Huskers within 33-26 at the half, and it was a five-point game after he made a couple of free throws early in the second half.
"I don't think our defense is the problem," Sadler said. "Offensively is the problem. You're not going to beat anybody scoring 44 points or 40 points. You ain't going to beat anybody. We've got to find a way to score some points. We held them to 64 points. Our issues are scoring baskets. It ain't going to be stopping people."
McCray led the Huskers with 16 points and nine rebounds. But like almost everyone else that plays Wisconsin, points were at a premium.
Wisconsin extended its streak of holding opponents to 65 points or less to 18 games. The nation's top defensive team, Wisconsin has held 12 of 14 opponents to season lows in points.
Nebraska's previous low was 51 against Florida Gulf Coast.
Wisconsin coach Bo Ryan said other than the first 3 minutes of the first and second halves, it was the Badgers' best defensive performance of the season. Nebraska's 14 second-half points were its fewest in a half since scoring 11 in the first 20 minutes against Creighton in December 2006.
The season-high crowd of 10,812 at the Devaney Sports Center began filing out with 5 minutes left and the Badgers leading by 23 points.
Nebraska needed, and got, more scoring production from McCray because of injuries that kept two of their top four scorers on the bench.
Center Jorge Brian Diaz sat out with sore feet and guard Dylan Talley missed the game with a thigh bruise. The Huskers also were without 6-11, 310-pound Andre Almeida, who has been limited because of nagging knee problems.
In a pregame ceremony celebrating the first Big Ten game, former Nebraska players were introduced to the crowd and then formed a line between the locker room and arena, welcoming the current Huskers to the court with handshakes and high-fives before tipoff.
Nebraska also played Wisconsin in its Big Ten football opener, losing 48-17 in Madison.