Did you enjoy your fill of heavyweight fights that were on the light side this past April? Neither did I.

Luckily, Showtime, Top Rank and Gary Shaw Productions have provided the perfect remedy: a lightweight fight packing plenty of heavy artillery. That’s exactly what Jose Luis Castillo and Diego “Chico” Corrales plan on bringing into the ring tonight at the Mandalay Bay in Las Vegas.

It’s only fitting that the WBC/WBO unification match was twice postponed. Its new date falls on the Cinco de Mayo weekend, and the fight figures to be far more fiesta than siesta. It is also universally regarded as a can’t-miss candidate for Fight of the Year.

Those who point to a Corrales win first cite his newfound ability to switch from puncher-boxer to boxer-puncher as necessary. Chico credits the transformation to veteran trainer Joe Goossen. “Joe is like a mad scientist. He pulls things apart,” was how Corrales described a tutorial session with one of the game’s premiere trainers. It was obviously a lesson learned. Since training under Goossen, Corrales is 2-0, avenging a 2003 loss to Joel Casamayor, and rallying back to force previously unbeaten Acelino Freitas into submission in their WBO lightweight fight last summer.

The Freitas fight was the last for Corrales (39-2 32 KOs), who will have been out of the ring for nine months by the time the opening bell rings tonight. How the layoff will affect him seems to vary according to who you ask. Corrales would rather he was more active, but believes that everything happens for a reason, that the fight was meant to take place in May 2005, and not a moment sooner.

“Obviously, I’ve been miserable for the past nine months or so,” admits Corrales. “I’m the type that likes to stay VERY busy. Give me a month, two months top, before putting me back in the gym and eventually into the ring. Nine months? It’s been difficult to maintain my sanity, especially watching Casamayor and (Julio) Diaz participate in fights I knew should have been mine.

“But you know what? Perhaps this is how it was meant to be. Maybe something goes wrong in December, and I wound up losing my title. The things that prevented me from returning to the ring did bother me a lot, but I just try to remain positive. They must have happened for a reason. I was meant to fight in May, on Cinco de Mayo weekend, so I embrace it as such.”

Trainer Joe Goossen has a somewhat similar take.

“The layoff is a double-edged sword,” he says. “Yes, Castillo has been busier in the past nine months, but he’s also been in three straight tough fights with no downtime. Corrales, meanwhile, gets to rest, and who knows . . . maybe Diego is a little fresher, and Castillo is a little more worn-out come fight time.”

If anything could be said of Castillo (52-6-1 46 KOs) it’s that he’s done more at lightweight to lay claim as THE champion in the division than has any other fighter in recent memory. His brawl with Juan Lazcano last June was followed up with his tougher-than-expected war with Joel Casamayor on Showtime last December. It was meant to be against Corrales, but the fight was postponed after Corrales’ camp balked at the money being offered.

Castillo was willing to fight him three months later. This time Corrales found himself in the middle of a power struggle. Banner Promotions obtained three options on his career following the Freitas fight and sought a good chunk of his purse for the proposed March fight. After tallying up how much he would have to pay to two promoters, a trainer and manager, Corrales realized that he’d be making less than everyone else involved.

Once again, the highly anticipated lightweight showdown was postponed. When Chico stepped aside, IBF lightweight champ Julio “The Kidd” Diaz stepped forward. When he did, the IBF decided to strip him of his title for pulling out of a mandatory defense against Leavander Johnson. Whatever, said Diaz, who chased the Showtime date in March, and the opportunity to knock off Castillo.

Bad decision, as Castillo took over midway through the bout and beat the fight out of Diaz, who wound up succumbing in the tenth round following two brutal knockdowns.

Corrales, meanwhile, had earlier signed to fight the winner in May. “It doesn’t matter who wins. I just want the fight,” proclaimed Chico. “I’m taking this fight for my fans.”

Once Corrales got his house in order, the long-awaited unification match with Castillo was finally on for May 7. Though most recognize the pair as the best two lightweights on the planet, opinions vary on the divisional leader.

The Ring magazine rates Castillo as its champion, by virtue of his win over then #2 contender Juan Lazcano last June. Those who support Castillo recognize him as the leader of the pack, with Chico fighting for his title of “people’s champion.”

Corrales’ camp has a different view.

“This fight pits the two best lightweights together, and the best will be decided on May 7,” insists Gary Shaw, who serves as Corrales’ promoter. “I respect Castillo’s run going into this fight. But the fact of the matter is that the champion of this division will be decided on May 7, and not a moment sooner.”

Shaw boldly predicts that the champion will reside under the Gary Shaw Productions banner: “Castillo is probably the toughest fighter that Corrales has ever faced, and the same can be said in reverse. But when all is said and done, my guy will knock out their guy and bring home all of the belts.”

Top Rank, naturally, has a different view.

“Look,” says Hall of Fame promoter Bob Arum, who promotes Castillo, “I’ve been hearing for the longest time about how everyone is going to take out my Mexicans. Jorge Arce was supposedly in over his head at flyweight in his March fight. Manny Pacquiao was going to knock out Erik Morales that same night. Kermit Cintron was supposed to knock out Antonio Margarito. It’s been proven before, but let me say it so everyone gets it: NOBODY KNOCKS OUT MY MEXICANS!”

At least not too recently. Prior to his championship run, Castillo was stopped four times. In his defense, all the stoppages were due to cuts, and he has not been dropped or stopped since 1998, having peeled off a run of 19-2-1 (14 KOs) during that stretch. His only two losses have come against Floyd Mayweather Jr. in 2002. Floyd was also the first person to defeat Corrales, dropping him five times before Diego’s corner ordered referee Richard Steele to stop the contest.

The loss was the first of two early stoppage defeats Corrales would suffer, with the first Casamayor fight in October 2003 being the other. Both stoppages were against Corrales’ will, particularly the Casamayor fight, where he had the Cuban visibly shaken toward the end of the sixth round in their multi-knockdown war. Many observers believed that Corrales needed just one more round to put Casamayor away. Unfortunately for Chico, Dr. Margaret Goodman had other ideas, as she ordered the fight to be stopped between rounds. Corrales had suffered a huge gash that split his lip open. Goodman feared that Corrales was already swallowing too much of his own blood and instructed Tony Weeks to halt the contest after six.

Like the Mayweather fight, the first Casamayor fight took place in Las Vegas. Chico calls Sin City his new hometown, but his next win there will be his first in over five years. His March 2000 stoppage of Derrick Gainer was the last time Chico had his hand raised in a Vegas ring, while Castillo’s last three fights on The Strip resulted in victories. In fact, this fight will be the third straight at the Mandalay Bay for “El Temible.”

Some fear that Castillo will suffer burnout, that four tough fights in eleven months will ultimately take its toll. Castillo understands the concern, but insists that there is nothing to fear – other than “The Fearsome One” (translation for “El Temible”).

“I’ve been training way up in the mountains for this fight,” says Castillo, who has been averaging a fight every nine weeks since the second Mayweather loss in 2002. “We had a real good training camp and I am looking forward to what I consider to be a great fight. But there is no doubt in my mind that I am coming out the winner.”

If Corrales agreed, he’d be the first fighter in the history of the sport to openly concede defeat before the first bell.

“A win over him would be awesome. It would be huge to me. I have been working very hard for this thing and I am determined to win it because he is such a great fighter and such a great, great champion,” Corrales says about Castillo. “Come hell or high water, I am leaving with the WBC and the WBO belts.”

They agree to disagree, much like the “experts.” What everyone agrees on is the fight becoming an instant classic. Suffering through the doldrums of April showers, this is one May flower that will bloom like no other.

(Note: The Castillo-Corrales unification bout headlines a full weekend of events at the Mandalay Bay. On May 6 (the night before) the arena also plays host to the 80th Annual Boxing Writers Association of America Awards Dinner.)