UNLV’s once promising season has suddenly turned into a fight to stay in the top half of the Mountain West.

UNLV rolled through a pathetic non-conference schedule to an 11-2 record. But the Rebels are just 2-2 in conference play, with wins over bottom feeders Air Force and San Jose State.

Aside from turnover issues at San Jose State and Air Force and poor three-point shooting against Boise State and Utah State, the offense has been rolling along. The Rebels problems stem from the defensive side of the ball.

The primary issue is UNLV’s interior defense. Throughout non-conference play, UNLV’s goal was to force tough two pointers. The Rebels were running teams off the three point line and hoping the defense was good enough to prevent easy layups.

Against opponents like Florida A&M and Mississippi Valley State, that defense was effective. But now, UNLV is getting torched inside.

Only one team, Arizona, shot over 50 percent on two pointers against UNLV in the first 12 games of the season. Over the last five game (including Northern Colorado and Mountain West games) UNLV has allowed four teams to connect on 50 percent or better on two pointers.

Utah State, which came to Las Vegas and delivered a gut punching 85-78 loss, scored on 61.8 percent of two point shots. The Aggies exploited UNLV’s defense by spreading the floor and making all five defenders guard to the three point line.

After the initial down screen, Utah State doesn’t have a single player step foot in the lane until the final drive for a score. The spread and drive style has crushed UNLV this season, as the Rebels lack any solid on ball defenders.

Utah State took advantage of Brandon McCoy’s lack of mobility. Rather than let seven footer anchor himself in the paint, the Aggies made him work.

Just on that play McCoy has to deal with the initial screen in the paint, then defend a dribble hand off. Next comes a ball screen, which leads to McCoy trying to close out on a three-point shooter.

It was an awful close out followed up by horrific help defense from Mooring and Juiston at the rim. But the play exemplifies how Mountain West teams have made Brandon McCoy a defensive liability. Make him move. Make him defend all the way out to the three point line.

Even Marvin Menzies has taken action to eliminate the liability, by taking McCoy out of games.

Against San Jose State, Mbacke Diong subbed in for McCoy for a critical defensive possession in the final minute.

Diong, in limited minutes, has been better defensively than McCoy. He is quicker than McCoy, which allows him to provide help defense and still recover back to his man.

Plus Diong has the leaping ability to make highlight blocks, where McCoy is a stationary defender.

Against Air Force, Menzies tried out a non traditional defense that would help keep McCoy closer to the basket. Menzies referred to the defense as a man-zone hybrid.

But it did not work, as Air Force shot above its season average percentage on two pointers. Even with McCoy spending most of his time in the paint, Air Force had no issue shooting over or around him.

Ultimately, McCoy has not been a good defender, and Mountain West teams have managed to exploit that weakness. But McCoy’s teammates haven’t helped him very much.

McCoy’s rim protection is the last line of defense from opponents’ two pointers. The first line – on ball defense – has been non existent.

Both Chandler Hutchison (32 points) and Koby McEwen (21 points) were named Mountain West player of the week after lighting up UNLV’s defense.

Between Jordan Johnson, Jovan Mooring and Kris Clyburn, UNLV lacks a true shutdown perimeter defender. Johnson and Mooring lack the size to handle a 6-foot-7 Hutchison and Clyburn has not developed into the defensive wing UNLV needs.

That hole in the roster has left McCoy looking bad, as he is left to defend some of the conference’s best players driving full speed to the rim.

UNLV has one other major defensive flaw: rebounding. Despite ranking 15th in the nation in total rebounds per game, the Rebels are a bad defensive rebounding.

UNLV allows opponents to grab 32.6 percent of their own missed shots, which ranks 293rd in the country. The national average is 29.1 percent.

When comparing two team’s rebounding in a game, don’t use total rebounds. Or compare each team’s offensive rebounds against each other. Both are a flawed way of examining rebounding. Always compare one team’s offensive rebounds against the opponent’s defensive rebounds and vice versa.

UNLV simply lacks good rebounders; Shakur Juiston may be the team’s only good defensive rebounder. Even McCoy, who racks up high rebound totals, isn’t a solid rebounder. He rarely blocks out, as most of his rebounds come from simply being taller than everyone else.

Ken Pom tracks defensive rebounds by position, and McCoy is the least of UNLV’s rebounding worries.

UNLV has some of the worst rebounding guard in the nation, which is to be expected when the top three guards on the roster are all 6-foot-2 or shorter.

Menzies has emphasized getting his guards to pinch in and help out on the glass, but it is ultimately up to Juiston and McCoy to keep teams from getting second chance points.

That becomes even more difficult when teams spread UNLV out and keep the bigs out of the paint.

UNLV’s offense ranks 60th in efficiency. The defense is just 136th. If the Rebels are going to make any sort of run in the Mountain West, the defense has to see drastic improvements.