Nebraska guard Cam Mack pushed up the floor with under 10 seconds remaining, having just left Maryland men’s basketball guard Anthony Cowan in his wake with a crossover.

Down 71-70, Mack seemed to have a clear path to the rim for a potential game-winning layup. That was until forward Jalen Smith helped off the player he was guarding and elevated for a game-preserving block, en route to the Terps’ 72-70 victory.

Smith’s defensive play was one of few highlights on that end of the floor. It likely wouldn’t have been necessary, if not for Maryland’s porous and lackluster effort on defense that allowed the Cornhuskers to hang around in the first place.

“You just kept thinking we were going to get it going defensively, because that’s what we do,” coach Mark Turgeon said. “We never did.”

[Read more: Maryland men’s basketball knew Nebraska wasn’t a “big game.” It nearly cost a win.]

The Terps boast the nation’s fifth-best adjusted defensive efficiency, according to advanced basketball statistics website Kenpom. But in the second half, against a 7-16 Nebraska team, a No. 9-ranked Maryland team couldn’t make stops and allowed the Cornhuskers to nearly overcome a double-digit lead.

Turgeon admitted after the game his team didn’t respect Nebraska enough from the start. But the Terps still opened up a 13-point lead at halftime, which only perpetuated the relaxed feeling that led to defensive lapses.

“We just relaxed,” guard Eric Ayala said. “Moving forward, we can’t have those types of games where we relax. Every game should be a big game for us.”

[Read more: One week after staying late for extra shots, Eric Ayala’s work paid off]

After just 25 points in the first half, the visiting Cornhuskers followed with a second-half onslaught of 45 points — the most the Terps have surrendered to any team in a half this season.

Nebraska’s roster doesn’t feature a player over 6-foot-9, yet the Cornhuskers repeatedly exploited openings in the paint. They poured in 24 points around the rim in the final 20 minutes, fueling their rally.

Ayala and Cowan pointed to backdoor cuts and a failure to keep the ball in front of them on the perimeter as the issues that festered during the uncharacteristically inept defensive performance.

If not for Smith’s block in the final seconds, Cowan’s inability to keep his man in front of him could have cost Maryland a victory. When asked about Smith’s block after the game, Cowan pointed out his own mishap that required Smith to make that play.

“I’ve got to keep the ball in front of me. This game right here was probably the worst defensive game I’ve had in my four years here,” Cowan said. “And that’s a wake-up call for me. Not only as a player on this team, but as a leader on this team, I’ve got to be better.”

Cowan will need to refocus quickly, as he prepares for a matchup against Michigan State’s star guard Cassius Winston on Saturday. Winston is third in scoring in the Big Ten, with 18.3 points per game.

Winston is the conductor of a well-run Spartans offense that shares the ball — ranking first in the conference in assists per game — and hits its shots at a 45.4 percent clip, good for second in the Big Ten.

The Spartans were the preseason No. 1 team in the country, but have fallen off steeply since. Despite the lack of a number next to the name, Maryland knows Michigan State isn’t Nebraska, and it can’t afford another defensive outing like the one it put forth on Tuesday.

“It wasn’t our typical defensive type of game,” Smith said. “They got a lot of wide-open shots on us. But it’s just something we’ve got to watch about and fix it and just figure out what we did so wrong this game.”