ATLANTIC CITY — Sometimes you sleep with the enemy and sometimes you just knock ’em out.

Those were some thoughts that came to the fore at Boardwalk Hall on Thursday night as Xavier coach Chris Mack and his Dayton counterpart Archie Miller led their teams through practice sessions on the eve of tonight’s showdown in an Atlantic 10 tournament quarterfinal here.

Miller, in his first year with UD, had never set foot in this storied arena. “I’ve seen this place on ESPN and heard the stories,” he said. “It’s been a big boxing place, hasn’t it?”

It certainly has.

The fistic Who’s Who that’s been in the ring here — champs like George Foreman, Mike Tyson, Lennox Lewis, Evander Holyfield, Sugar Ray Leonard, Roberto Duran, Oscar De La Hoya, Arturo Gatti and his trilogy mate Mickey Ward — goes on and on.

When I mentioned Tyson’s 1988 heavyweight demolition of unbeaten Michael Spinks in 91 seconds here, he lit up.

“We’ve shown that clip to a lot of teams I’ve been with,” he said. “That’s one of the best you can show. When you watch Tyson enter the ring, that stare in his eyes and the other guy just wetting his pants (before the bell) — that fight was over before it started ... Now THAT’S mentality.”

Tyson needed just eight punches to put Spinks down twice, the last flattening closing his eyes and ending the bout and his career.

Asked if he’d shown his team that clip, Miller shook his head: “I don’t know if our men quite grasp that one yet.”

But now might be the time. If the 20-11 Flyers can keep winning, they can hold that tenuous line to the NCAA tournament. Two wins here might get them there, three — and the tournament title — certainly would.

The fact that tonight’s game is with backyard rival Xavier adds to the buildup. Then there’s the coaching connection. Mack was on Sean Miller’s staff at Xavier. Archie is Sean’s younger brother.

While both have shared laughs and now a mutual respect, all that’s put aside a bit during the season, they said. “Truth be told, when you’re the Dayton coach and the Xavier head coach it’s hard to be close,” Mack admitted.

Yet, you point out, Mack’s wife is the former Christi Hester, one of the greatest women’s basketball players in UD history.

And so, might he actually have some Flyers stuff in his closet?

“Not in my closet!” he said with a grin. “But you know what? She’s got an old coat I think they probably gave out for a team coat for winter travel. I usually step on it every once in while...”

With a pause, he ’fessed up: “Naah, not really.”

But you do sleep with a Dayton Flyer every night, right?

“That is true,” he said as the sound of his laughter rose up into this storied hall where sleep hasn’t come so much to those connected by a wedding band as it has to those connected on opposite ends of the same big punch.