NEW YORK – Over the past two decades Cedric Kushner has carved out his own specialized niche in the boxing world. Whether he’s called them ‘Heavyweight Explosions’ or, in the case of Wednesday night’s card at the Manhattan Center, “Heavyweight Extravaganzas,” the South African-born promoter has turned collecting second-tier heavyweights into a veritable art form.

Expectations are understandably modest. The widespread assumption is that if these heavyweights were that good they’d probably be with another promoter in the first place. Sometimes, even the heavyweights themselves appear to share this view, the most obvious case being Hasim Rahman, who knocked out Lennox Lewis to win the heavyweight title only to leave Kushner in the lurch, having been lured away by Don King and the infamous duffel bag full of cash a few short weeks later.

But Kushner’s shows provide a certain comfort zone for both would-be contenders and those on whose careers the sun has begun to set. And sometimes, as in the case of David Tua, both.

Kushner promoted Tua early in his career and managed to hook up with him again once the New Zealand veteran began to descend the ladder. His appearance against Illinois veteran Edward Gutierrez on Wednesday’s Gotham Boxing show was Tua’s first outing since he was life-and-death in edging Cisse Salif nine months ago in Florida.

By now you’d have to say that, like water seeking its own level, Tua has pretty firmly established his position in the heavyweight pecking order, which is to say that he couldn’t beat Lennox Lewis or Chris Byrd, but he can beat Michael Moorer and Fres Oquendo.

What does this make him, then? Well, for the moment it made him a Cedric Kushner heavyweight. It wasn’t that long ago that Tua was headlining against Lewis in a title fight at the Mandalay Bay, and now here he was returning to New York as the opening act for an ESPN2 card.

Of course, Shannon Briggs was originally supposed to be boxing on this card as well, but Briggs was abruptly snatched up as the opponent for Wladimir Klitschko in a WBC title bout at the Garden this fall, and wasn’t about to take any chances, even though Klitschko fight is four months away.

“What if I hurt my hand or something against one of these guys?” Briggs grinned slyly as he explained his defection.

But if Briggs can be rehabilitated for a title fight, why not David Tua?

Beset by managerial problems, Tua took a two-year hiatus from the ring after his 2003 draw with Hasim Rahman. He returned to New Zealand, got married, and, he says, “got away from the game for a while.”

Always short and squat as heavyweights go, Tua has the build of a smallish sumo wrestler. When he removed his robe just before the Gutierrez fight, one was tempted to note that the new Mrs. Tua  must be an excellent cook, but the 245 he weighed for this one is pretty much in line with what he’s weighed for the past half-dozen years, going back to the Lewis fight.

Tua came out against Gutierrez looking like a man determined not to expend any unnecessary energy, flicking away with jabs as he assumed a leisurely pursuit of his retreating foe.

In the second round, Tua caught up with Gutierrez long enough to send him down with a left hook, but, almost surprisingly, let him off the hook. Tua has historically been a great finisher (ask John Ruiz about that), but on this night he didn’t appear to be in any great hurry.

“I wanted to stay patient and give myself a chance work on some of the things I’ve been doing in the gym,” Tua would say later.

Like the combination that ended the fight?

“How did you know?” he replied with a grin.

Late in the fourth, Tua lashed out to thud a hard left hook off the side of Gutierrez’s head, and in the split-second his foe stood there wobbling, followed it in almost the same motion with a hard left to the body.

Gutierrez sank to all fours and remained there while Mike Ortega counted to ten.

“I don’t know if you saw that (Salif) fight in Florida last year, but this was like night and day compared to that,” said matchmaker Jim Borzell.

It was the third straight loss for Gutierrez (15-3-1), who had previously dropped back-to-back decisions to J.D. Chapman after going undefeated through his first 16 fights.

So where does Tua go from here? He’s only 33. He’s 45-3-1, with the losses coming at the hands of Lewis, Byrd, and Ike Ibeabuchi, none of whom he is likely to cross paths with again. Beating Edward Gutierrez might not prove a lot, but for our money Tua did demonstrate that he may have more left than previously suspected, in which case Cedric probably ought to start looking over his shoulder right now.

Hall of Fame trainer Emanuel Steward knew that he was rolling the dice by testing his undefeated young cruiserweight Johnathon Banks against the wily Cuban veteran Eliseo Castillo, and a couple of minutes into the main event of the Wednesday Night Fights telecast Manny may have been rethinking his decision.

Twice in the first round Castillo penetrated Banks’ defenses to put him on the floor. A short, crisp right sent Banks tumbling to the canvas a minute into the fight, and shortly thereafter Castillo clocked the Kronk fighter with another right that sent him down face-first.

Although Banks appeared to be in a world of trouble, he insisted later that he had not been hurt, and the balance of the contest would seem to bear that out. Banks won the next two rounds on our card, anyway, and then in late in the fourth, he stung Castillo with a left hook and than waded in to flatten him with a solid left-right combination. Castillo slumped into a neutral corner, where he was counted out by Eddie Cotton at 1:12 of the round.

“It was one of the most satisfying wins of my career as a trainer,” said Steward afterward. “Castillo was bigger and more experienced.”

Indeed, Castillo had campaigned mostly as a heavyweight of late, and had lost only to Wladimir Klitschko, but Banks, now 12-0, said he was “never worried,” despite the first-round pummeling.

“During training camp I dreamed several times that I got knocked down in this fight,” he revealed. (Or did he dream in training camp that he’d get knocked down several times?)

“My mother, my brother, and my sister were all here,” said Banks after the impressive win. “I wasn’t going to lose this fight.”

The loss was his first-ever to another cruiserweight for Castillo, now 20-2-1.

Peter Quillin, the unbeaten New York middleweight who has appropriated the time-honored handle “Kid Chocolate,” starched his Ohio opponent William Prieto with a right hand, knocking him out at 1:06 of the first.

Happily for Kid Chocolate, his swing bout was unexpectedly promoted to the ESPN2 telecast after Tua finished off Gutierrez early.

“I feel like I was made for television,” said Quillen, who improved to 6-0. (Prieto is now 2-1.)

Jorge Teron’s fight against Florida journeyman Armando Cordova also made it onto the telecast, and the Bronx lightweight prevailed with a unanimous if untidy decision, winning 58-56 three times (John McCaie, Matt Ruggero, Don Trella) to remain unbeaten at 11-0-1. Cordova slipped to 21-26-2.

Brooklyn lightweight Cindy Serrano was spotting Tawnyah Freeman five pounds and several inches in height, but more than offset the physical disparity with her advantages in speed. Often landing two and three punches to Freeman’s one, Serrano counterpunched so effectively that as the bout wore on Freeman became increasingly reluctant to pull the trigger.

Although there were no knockdowns, Serrano won with relative ease, with George DeGabriel and Ruggero both scoring it 59-55, McCaie 60-54. (The Sweet Science card also had it a shutout at 60-54.) Serrano is now 11-0-1, Freeman 7-3.

Preceded into the ring for his pro debut by a marching color guard of fellow gyrenes in dress blues, Yonkers heavyweight Jon (The Fighting Marine) Schneider marched back out a minute and five seconds later, having laid waste to his Milwaukee victim Eddie Kimbrough (0-2). The two novice heavyweights traded nonstop leather while it lasted, but when Schneider caught Kimbrough with a solid right and followed it up with a left-right combination, he put him away for the night.

Moments later, The Fighting Cop picked up where The Fighting Marine had left off, as another Yonkers boxer, super-middleweight Bryant Pappas, decked Kentuckian James Durham four times before Ortega rescued The Louisville Slugger a second before the first round would have expired. Pappas is now 4-0, while Durham fell to 0-2.

The walk-out bout saw Queens middleweight “Mean” Joe Greene go to 11-0 with a second-round TKO of Omaha southpaw Damone Wright (17-26-2). Greene floored Wright twice in the first round, and then early in the second dropped him with a left hook delivered with such force that Cotton dispensed with a count and waved it off (at 0:29 of the round) the instant Wright hit the canvas.

JULY 26, 2006

HEAVYWEIGHTS: David Tua, 245½, South Auckland, N.Z. KO’d Edward Guitierrez, 227, Oak Lawn, Ill. (4)

John Schneider, 197½, Yonkers, NY KO’d Eddie Kimbrough, 230, Milwaukee, Wisc. (1)

CRUISERWEIGHTS: Johnathon Banks, 197, Detroit KO’d Eliseo Castillo, 196, Havana, Cuba (4)

SUPER MIDDLEWEIGHTS: Bryant Pappas, 164, Yonkers, NY TKO’d James Durham, 164, Louisville, Ky. (1)

MIDDLEWEIGHTS:  Joe Green, 159, Jamaica, NY TKO’d Damone Wright, 159, Omaha, Neb. (2)

Peter Quillin, 160, New York KO’d William Prieto, 160, Cincinnati, Ohio (1)

LIGHTWEIGHTS: Cindy Serrano, 130, Brooklyn, NY dec. Tawnyah Freeman, 135, Fort Smith, Ark. (6)

Jorge Teron, 135, Bronx, NY dec. Armando Cordoba, 135, Darien, Panama (6)