Before the season, Maryland men’s basketball coach Mark Turgeon was quick to point out to his team that last year’s national championship game featured two of the top defensive squads in the nation.

Virginia allowed the fewest points per game in the country, and Texas Tech was just two spots behind. No one held opponents to a lower field goal percentage than Texas Tech.

Turgeon’s message was cliche, but simple: Defense wins championships. And the Terps’ defensive effort for the majority of this season has propelled them to the cusp of a Big Ten regular-season championship.

But with three losses in its last four games — the lone win coming in a dramatic 17-point comeback against Minnesota — Maryland’s defense may ultimately be what prevents the team from winning that championship.

“We’re not guarding. We guarded the last 10 minutes of the Minnesota game, [but] we really haven’t guarded for the last three and a half games,” Turgeon said. “We have till now and Sunday to figure that out.”

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When the Terps take the Xfinity Center court for their regular-season finale against Michigan on Sunday, the Big Ten title that seemed all but wrapped up will be on the line. With a win, Maryland can still claim a share of the conference title, and it could even still win it outright if other results go the team’s way.

But just last week, even after the loss to Ohio State, the Terps had a two-game lead atop the standings and a stronghold on their own fate.

One win in the final three regular-season games meant a share of the conference title. Two wins meant the program’s first outright conference regular season championship since 2002. But two consecutive losses suddenly brings a level of anxiety to Sunday’s game.

“I think it’s just the weight of everything,” Turgeon said. “But we can’t feel sorry for ourselves, we got to go get it.”

If Maryland wants to avoid letting the regular-season title slip away entirely, it will need to return to the defensive effort that brought it to the brink of clinching in the first place.

The Terps have allowed opponents to score over 70 points in four consecutive games, the longest such streak of the season. During the three losses in that span, Maryland has allowed a season-high 79 points once and 78 twice.

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Before the recent stretch, Turgeon’s team had surrendered 70 or more points just seven times in the first 26 games.

“We can definitely fix it,” guard Anthony Cowan said. “We’ve just got to get back to what we [were] doing in the beginning of the season. On the defensive, we’ve really been struggling. We’ve got a lot of room for improvement. We’ll get there. We’ll get there for sure.”

The difference in the past four games has been the number of opposing shooters finding wide-open shots. Whether it’s ball movement that creates an open 3-pointer, or a pick-and-roll that opens a driving lane, the Terps’ defense has been a step slow in rotations.

“We’re not playing like our normal selves,” forward Jalen Smith said. “We’re letting a lot of things slip. A lot of our principles that we’re supposed to abide, we’re not really following.”

Turgeon has offered other explanations for the recent defensive struggles.

Against Ohio State, Turgeon harped on forward Kaleb Wesson’s ability to “bully” his way around the paint and impose his will.

Days later in Minnesota, the ninth-year coach said players who the Terps didn’t expect to make threes ended up doing so.

In Saturday’s loss to Michigan State, the Spartans shot 47.5 percent from the field. Turgeon said Tuesday that he doesn’t think any team would have beat Michigan State that night with the way it played.

And in the loss to Rutgers, his team let the offensive struggles affect its proficiency on the defensive end of the floor.

Turgeon has offered those defensive responses about his unit. Now, he’ll need his defensive unit to respond and prove that these last four games were aberrations and not the makings of a larger problem that will persist through the regular-season finale and beyond.

“It’s just a mindset,” Turgeon said. “We’ll get it right.”