The Georgetown Hoyas had plenty of reason to be riled up for Saturday afternoon’s game at Capital One Arena.

Southern Methodist was the last of the Hoyas’ three expected tests of the nonconference schedule, following games with Illinois and Syracuse. Georgetown was looking to take out some frustration in its first game after a devastating loss to the Orange last weekend. And a boisterous announced crowd of 6,763 made Saturday’s matchup feel like the Hoyas’ first proper home game; it wasn’t the biggest of the season, falling a bit short of the attendance against Campbell two days after Thanksgiving, but it was the loudest by far.

Yet Georgetown looked out of sorts from the moment it stepped onto the court. The Hoyas’ defense let them down, and their clunky offense failed to make up the difference in an 81-73 loss, their first defeat of the season at home.

“Couldn’t stop anybody,” said Coach Patrick Ewing, the lone Georgetown representative to address members of the media after the loss. “They just put their head down and were able to get to the basket a few times on pick and rolls. We didn’t play the way that we talked about in the shoot-around or in practice. They were able to slip out and get layups; no one came over and took charges. So it was just, to me, a total breakdown.”

Jessie Govan led the Hoyas with 17 points to go with seven rebounds. Freshman guards James Akinjo (16 points, seven rebounds) and Mac McClung (13 points) made up the bulk of the rest the Hoyas’ offense.

Another freshman, forward Josh LeBlanc, was one of Georgetown’s few bright spots with nine points, a team-high nine rebounds and two big blocks, but otherwise the Hoyas (7-3) struggled on defense. The Mustangs shot 47.5 percent from the field and made 10 of 25 three-point tries. Despite the Hoyas’ size advantage, SMU outscored Georgetown in the paint 32-30.

Given its poor defense, Georgetown never had control, even when it went on runs. The Hoyas whittled a 13-point second-half deficit to three with 2:18 to play, but every time they had an offensive burst, defensive ­mistakes let SMU (7-4) back in.

“We cut the lead to two or three, and then you know, a few turnovers, missed shots, didn’t get back and get stops,” Ewing said.

Georgetown allowed the opponent’s leading scorer to get hot after halftime for the second game in a row. A week after Syracuse leading scorer Tyus Battle dropped 21 second-half points on the Hoyas, Mustangs guard Jahmal McMurray led SMU with 19 points, 13 of which came after halftime. Forwards Isiaha Mike and Ethan Chargois had 17 points each.

Ewing said that his team’s ­defensive breakdowns weren’t because Georgetown doesn’t know what to do; after all, the Hoyas just had a week of practice between games. Georgetown was simply out of whack.

The Hoyas looked off even before tip-off Saturday, the first clue being that Ewing had benched starter Jamorko Pickett. The sophomore wing arrived on the court in a suit for the first time in his Georgetown career, rather than the alternate “tidal blue” uniforms the Hoyas sported Saturday. (The alternate uniforms were a nice nod; Georgetown commonly sported the lighter-blue uniforms in the mid-1980s, and the last time the Hoyas played the Mustangs was in the 1984 NCAA tournament en route to the national title.)

Pickett was one of the Hoyas’ most promising players as a freshman but has faded into the background this year, having taken just 43 shots all season, an average of less than five per game. When asked what led to the decision to bench him, Ewing simply replied “coach’s decision” and smiled.

Kaleb Johnson started in Pickett’s place, and the shake-up in the starting lineup only seemed to add to Georgetown’s off day.

When asked what Georgetown needs to improve with three games left — against Appalachian State on Tuesday, Little Rock on Saturday and Howard on Dec. 29 — before the start of Big East play, Ewing replied, “Everything.”

“We need to win games like this; we need to be able to stop people when we need to get stops,” Ewing said. “Teams like this are the teams we’re going to be playing when the Big East starts.

“So we need to step our efficiency up, execute our offense better than we did today. . . . Everybody knew what we were doing [on defense]; we just didn’t get it done.”