They say you should never bring a knife to a gunfight.

Well, the Lions didn’t; they brought a shotgun. Trouble is, the New Orleans Saints have a howitzer.

The Lions, 45-28 losers on Saturday night in New Orleans, didn’t get blown out because they don’t have a good offense. The Lions lost big because the Saints’ offense is better, and the Lions’ defense is still a work in progress. If the Lions defense was a freeway, three lanes would be shut down and it would be filled with orange cones.

Did you notice any glaring differences between the Lions and Saints, when it came to having the football?

Don’t look at the quarterbacks; Matthew Stafford and Drew Brees are pretty comparable.

Don’t look at the receivers; the Lions have the best one on the planet, but the Saints have a cache of good receivers in their own right.

Did you happen to notice that the Saints have something called a ground game?

Oh, what the Lions offense could look like, if they had someone to run the football with any consistency.

My kingdom for Stephen Jackson of the St. Louis Rams.

But we’ll just have to settle for a healthy Jahvid Best and Mikel Leshoure; which should occur next season, if Mr. Outside and Mr. Inside recover from concussion and Achilles injury, respectively.

The Saints gashed the Lions’ supposedly dominant defensive line with the run all evening, as if Brees needs any help.

And as if the Lions’ could have stopped him, even if your Aunt Mary were running the football.

Brees’ surgery on the Lions secondary was complete. The Saints quarterback wielded his scalpel to the tune of 466 yards passing and three touchdowns. He left the Lions looking like Gerry Cheevers’ goalie mask.

Now it’s up to GM Marty Mayhew to make sure another scene of carnage never happens again to the Lions in a playoff game. This was Mayhew’s Mulligan. He’s allowed this implosion, because his team is still just three years removed from 0-16.

But next year, and the year after, and the year after, it will no longer satiate the fan base to simply qualify for the playoffs. We’ve fallen for that once before, in the 1990s, when the Lions went one-and-out in the post-season five out of six seasons in the decade.

That won’t cut it, with a franchise quarterback and an All-Universe Receiver.

Mayhew’s charge, in a way, gets simpler with the more success the Lions find, yet it also gets harder.

It gets simpler because the holes are fewer on the roster, thanks to Mayhew’s astute drafting and slick trading and signings.

Yet it also gets harder because expectations have now been ratcheted up.

The Lions got carved up on Saturday and 626 total yards later, they were nothing but a carcass, the bones licked clean by the Saints’ well-balanced offense.

Mayhew has to draft for secondary help this spring, and he needs to find a new center and left tackle, to be on the ready when Dom Raiola and Jeff Backus retire.

There needs to be more roster massaging before the Lions can truly call themselves Super Bowl contenders. No one gets bumped out of the playoffs in the first round, as soundly as the Lions did, and comes back with the same cast and crew and expects to make progress.

This was no fluke loss. You can’t blame this one on the crazy bounces of an oblong pigskin.

The Lions were beaten, and beaten good, by the Saints, who are legitimately elite. The Saints are what the Lions would like to become, in short order.

The Lions can now check off “Make the playoffs” on their to-do list under the Mayhew/Jim Schwartz regime.

Next is, “Advance beyond the first round.”

The biggest challenge yet for Maywartz.