How do you blow an 18-point lead in the last five minutes of an NBA game?

The Charlotte Bobcats taught a graduate-level course in the subject Monday night, ultimately losing 118-112 in overtime to Portland. They had led 97-79 when the clock struck 5:00 in regulation, but after that did just about everything wrong.

Guards Kemba Walker and Ramon Sessions both said that Portland “out-toughed” the Bobcats. Coach Mike Dunlap fell on his sword, saying the team didn’t know how to handle a big lead late and that “100 percent of the blame” for that was on him. Dunlap also said the team had been “feeling its oats” and kept taking quick, outside shots late.

It was the sort of loss that would have fit right in with the 2012 Carolina Panthers’ season. Fans in Charlotte certainly walked out of the arena with a familiar air of bewilderment and disgust – a toxic combination that has already become the scent of the Panthers’ season.

The Bobcats wasted a lot of good work in the haunting loss.

Byron Mullens slammed home the most spectacular dunk of his NBA career. Ben Gordon had a rare four-point play as part of his 29 points. Walker scored more points in the first half (17) than his season average (16.3).

And still, the Bobcats messed it up.

The defeat also means that the unfettered feel-good era of these 2012-13 Bobcats is over. It lasted a month, which was enough time for the Bobcats to win as many games as they did all of last season.

But now reality has intruded. Once 7-5, the Bobcats are now 7-9 with two more likely home losses on tap for this week (New York and San Antonio) unless they start playing a lot better.

That 7-9 mark is still far better than 7-59 – their mark from a season ago that set a new NBA standard for futility. .

But even with all the new players in the rotation, these Bobcats aren’t a .500 team. They are destined to slip further below that line of demarcation as the season progresses. They are a young team that is all over the place, closing games like a champ on one night and giving up huge leads the next.

“We got sort of calm once we got the big lead,” Sessions said, “instead of attacking like we did to get the lead in the first place.”

The Bobcats seemingly had things under control for most of the night. They had the requisite dunk highlight (from Mullens on a vicious one-handed dunk from the free-throw line to posterize LaMarcus Aldridge), the dazzling ballhandling (Walker) and the hot 3-point shooter (Gordon, who had a franchise record eight treys).

But then Mullens and his teammates kept getting trounced on the boards late. “They got every big rebound,” Walker said. Portland’s 3-point shooters got rolling. Then Walker missed the last shot of regulation, a contested 14-footer that would have won it.

In overtime, the Bobcats’ loss seemed inevitable. Portland (8-10) was playing with house money at that point.

So the bottom line Monday was that the Bobcats showed 1) how far they have to go and 2) no lead is safe.

Mullens’ soaring dunk had at one point seemed like a nice symbol of a team on the rise, a team that was only five minutes away from evening its record at 8-8.

But then it all came crashing back to Earth.