KATY, Texas-The only thing consistent about Southeastern's Lions all season was their inconsistency.

Maddening, mystifying inconsistency.

On Thursday night, just days after taking down Northwestern State on its home floor during an impressive season-ending three-game winning streak, the Demons paid the Lions back by destroying them in the opening round of the Southland Conference Tournament.

The Lions were never in it as they fell behind by double digits in the first five minutes, came back to tie it, then fell apart as the Demons cruised to a 71-51 victory here in the Merrell Center.

"There really wasn't much to be said," said Lions assistant coach Roman Banks, filling in for head coach Jim Yarbrough in the post-game radio interview. "Our effort wasn't very good tonight. We weren't able match their intensity. They had several guys who were able to raise their game up to tournament level, and I don't think our guys matched that at all.

"Their level of play was much more higher than our level of play."

It was the third consecutive year the Lions (17-13) have gone one-and-done in the SLC tournament. The Demons (14-17) advance to play top-seeded Stephen F. Austin on Friday in the semifinals.

Seventh-seeded Texas-Arlington (19-11) pulled off the day's biggest upset, knocking out No. 2 seed Lamar 81-75. The Mavericks move on to play third-seeded Sam Houston State (23-7), a 64-62 winner in overtime over McNeese State.

The Lions were never really in it Thursday, sinking into a deep 17-point hole in the first half before going to halftime down by 15 at 43-28 . It was their largest first-half deficit in any game this season.

The Lions shot well in the first half - 9-for-15, 53 percent - just not enough, thanks to their 12 first-half turnovers. And with inside players Patrick Sullivan and Warrell Span each picking up two quick fouls, the Southeastern defense didn't produce as the Demons shot 60 percent (18-for-30) from the field, including 5-for-9 from 3-point land.

Colby Bargeman paced the Demons with 12 points and Trey Gilder added eight over the first 20 minutes.

And it never got any better. The Lions mounted a minor flurry to get within 11 points at one stage of the second half, but the Demons surged away again and never had to sweat over the final 20 minutes.

Gilder scored 18 points and had six rebounds to lead Northwestern State. Bargeman finished with 13, and Jerell Thomas netted 11.

The Demons put the clamps on Lions leading scorer Kevyn Green, holding him to 12 points. Span had 11 points and and Tavaris Nance had 10 points.

But Lions Sullivan was completely shut out, missing his only shot of the game - a layup - and posting twice as many turnovers (four) as he had rebounds (two).

The Lions finished 18-for-40 (45 percent) from the field, and just 3-for-13 (23 percent) from 3-point range. They also finished with 21 turnovers, including 11 NSU steals.

The Demons finished 30-for-54 (55 percent) overall, including 8-for-17 (47 percent) from outside the arc.