It’s been said that the weighting is the hardest part.

That might have ended up being the case for Diego Corrales, who started his star-crossed weekend with fateful, failed attempts to make the 135-pound limit for his fight against Joel Casamayor, who came to the scale and the ring right on target.

By the time Casamayor had captured a well-earned but debatable split-decision in their third Showtime broadcast encounter, a disillusioned Corrales seemed to be questioning the continuation of his fistic future.

“I thought I won,” said a much-deflated Corrales. “I was fine. I came out and boxed well, basically running on fumes. You’ve seen the end of me at 135.”

“I won the fight clearly,” said Casamayor. “I took charge with my jab from the beginning. The judges got it right this time.”

The contest didn’t feature the same fierce, two-way action as their first two fights but like the entire Casamayor – Corrales saga, it unfolded with plenty of bloody drama.

Sometimes the high-top boxing shoe is on the other foot or in the other mouth. Today that shoe was Corrales’s, on a last minute stipulated weigh-in scale. After coming in four and a half pounds over on multiple attempts Friday, Corrales made a new 147 pound limit at a High-Noonish Saturday appointment where he weighed 145½ to Casamayor’s 144½ just hours before the bell.

Old school style by accident.

Corrales forfeited his right to defend or win the IBF belt, plus a reported two hundred fifty thousand bucks, half of which got added to Casamayor’s take. Official weights were Casamayor 135, Corrales 139½.

Expatriate Casamayor appeared supremely confident in a Cuban flag cape as he hop-hopped his way into the arena.

Corrales looked like he was trying to feed off the energy of the crowd as he made his entrance.

After almost the entire three minutes of round one elapsed without a solid punch landed, action picked up consistently. The assembled swarm booed early but screamed in approval by the fight’s conclusion.

Corrales moved forward, but seemed too reserved. Casamayor worked mainly from the outside, darting in with increased frequency. Casamayor opened up more by round three and brought Corrales out of his shell.

A big left snapped Corrales’s head back in the fourth and woke him up a little more. A series of strong Corrales lefts put Casamayor back on defense.

A questionable knockdown was ruled against a slipping, astounded Casamayor in round five by referee Kenny Bayless, who otherwise did a good job letting them maul and brawl.

Heads clashed and tempers flared as a hyperactivated Casamayor got bolder at the midway point. His shaved head might have been as effective a weapon as his gloves in round six, as Corrales’s left eye was tenderized.

Casamayor took immediate note and aim. Corrales kept himself in the fight with strong rights.

Casamayor came in headfirst in the eighth and Corrales smacked him low, perhaps in direct response.

Each man landed big whaps down the stretch, Casamayor with a slight edge. Corrales sensed the finish line and increased his pressure. It seemed like he had a lot of ground to make up.

In the final frame they shuffled across the mid-ring “Rocky Balboa” signed canvas and traded with true cinematic flair. Casamayor withstood some huge shots, and though he bled from a cut nose by the end, it looked like Corrales’s rally fell short.

Scoring: Adalaide Byrd and Nubuaki Uratani favored Casamayor 116-111 and 115-112, respectively. Jerry Roth saw it for Corrales 114-113.

Corrales was stunned by the verdict, but the crowd sounded satisfied.

The split-decision seemed about right. The bruised pair showed mutual sportsmanship after the bout.

Drained Corrales, now 40-4 (33), dismissed any notion regarding his yearlong layoff, or the weight limit problem, but it definitely looked like retirement had become an option.

“I really thought I could make weight, obviously I couldn’t,” apologized Corrales. “I learned the hard way. [Now] I have to go home and think about what I’ll do next.”

A jovial, forgiving Casamayor, 34-3-1 (21), said he was more than ready to move on, and claimed he’s been calling out Marco Antonio Barrera for quite a while now.

“I knew they couldn’t take this from me because I won so clearly,” said Casamayor. “I was a little disappointed when Corrales didn’t make weight, but that didn’t make any difference. I came to win my title in the ring. What can I say? Diego’s a great guy. He’s got a family like I do. Anything I said before the fight was just business.”

The win puts Casamayor in the driver’s seat of a pretty nice ride.

Before tonight’s full moon rose over Mandalay Bay, it might have been more likely to see werewolf women on the prowl than Corrales transforming into Jose Luis Castillo.

For the record, lotsa lipstick fangs are generally bared late in the casino, lunar glow available or not.