EUGENE — Tyler Dorsey and Chris Boucher never lost at Matthew Knight Arena.

Oregon’s two deepest NCAA Tournament runs under Dana Altman followed perfect records at home. The Ducks were 18-0 at Matthew Knight Arena en route to the Elite Eight in 2015-16 before the Final Four team went undefeated in 17 home games the following season.

Oregon built a 46-game home winning streak that came crashing down early last season when Boise State’s Lexus Williams made a half-court shot for a 73-70 win. That turned out to be the first of three home-court defeats for the Ducks in a season that ended in the National Invitation Tournament, snapping a string of five straight NCAA Tournament appearances.

The Broncos were the first team from outside a Power 5 Conference to win at Matthew Knight Arena, but now there are two after Texas Southern stunned the 18th-ranked Ducks 89-84 on Monday.

“Last year around this time we dropped two quick ones and we did not make changes,” Oregon junior guard Payton Pritchard said. “It starts in practice. People are going to have to make changes.”

Last year, the Ducks defeated Texas Southern 74-68. They also had a softer nonconference schedule than this year with upcoming trips to Houston, Baylor and Boise State.

Regardless of Saturday’s result at Houston, Oregon will likely fall out of the Top 25 and the loss to Texas Southern — a 25-point underdog that lost by more than 30 at San Diego State and Gonzaga — will remain a stain on the Ducks’ postseason resume.

Oregon plunged 67 spots down to No. 106 in the NCAA’s new Net rankings that are used by the tournament selection committee beginning this season instead of the old RPI system.

Pritchard, the only player left from the Oregon Final Four team, did not hold back after Monday’s loss.

“Our intensity, we take days off,” he said. “Mentally, we don’t bring it and that needs to change. It shows in games.”

Pritchard and senior Paul White are the veteran voices on a team that also includes three sophomores, five freshmen and a graduate transfer.

“It is a different challenge,” Altman said. “If you are not going to compete and be more physical, it starts with coaching and the demands have to increase. We have to do a better job. We are so offensive-oriented. Our guys come off and they are all worried if they hit a shot or not. Getting stops and rebounds do not mean a lot to us and in the college game, that has to mean a lot.”

Oregon does not have the physical presence provided by MiKyle McIntosh, Jordan Bell and Elgin Cook in recent seasons.

Freshman Bol Bol is 7 feet 2 and a thin 235 pounds, while 6-10 freshman Miles Norris is likely to redshirt to add to his 210 pounds. The 6-9 White is admittedly more suited to play on the perimeter. Freshman Francis Okoro may be the most physical player on Oregon’s roster, but he has played only 10 minutes in the past two games.

Kenny Wooten was injured seven minutes into the loss against Texas Southern, whose 7-2 senior Trayvon Reed went 9-for-9 from the field, mostly on dunks, in scoring 23 points. Reed also had seven rebounds to lead Texas Southern to a 41-32 edge in that category.

“We never got physical with him, he did whatever he wanted,” Altman said of Reed. “That is the same way they beat Baylor, he was real effective in that game. With a guy like that, you have to get into his legs and be physical.”

Oregon has nine scholarship players with five-star freshman Louis King still yet to debut due to a knee injury. That number could be reduced if Wooten’s injury forces him to miss Saturday’s game at Houston.

“Our consistency has not been there,” Altman said. “We talk about it with the players. We don’t do things on a consistent basis. I know we have some young players but they are going to have to be more physical than that.”