Pound for pound punching-machine Juan Diaz, knee deep in a promotional beef with Don King, met Nate Campbell, a 36-year-old title fight veteran, in the chief support bout in Cancun, Mexico on Saturday night.

The tiff, shown on HBO underneath the Peter/Maskaev title fight, was supposed to be another showcase for the ascendent Diaz. Didn't turn out that way. The 36-year-old Campbell talked tough coming in to the match, and walked the walk. He was busier than the typically ultra-busy Diaz, and at the end of 12 rugged rounds, the judges got it right.

Fight fans, used to ludicrous examples of blatant larceny and/or incompetence, almost had a heart attack when they heard the first score, 114-113 Diaz. But we all breathed a sigh of relief when we heard the other two scores:  116-111  and 115-112 for Campbell.

The stats told the story: Campbell outlanded and outhrew Diaz, 414 to 288, and 1,145 to 891.

Diaz (33-0 coming in), a 24-year-old Texan, was defending his IBF lightweight title, which he took from Julio Diaz in October. Campbell, a Floridian, was a day past his birthday, and looking to secure his first major crown.

Diaz was 134 1/2, while Campbell weighed 134 pounds at the weigh-in. Diaz was without trainer Ronnie Shields, who broke his leg in Cancun, and Derwin Richards dispensed advice to the Texan in between rounds. Would the presence of Shields have changed things, we wondered? And would Diaz' head be in the game, we pondered, or would his promotional woes weigh him down?

HBO's Harold Lederman scored it 115-112, Campbell.

In the twelfth round, Diaz had to hold on several times; you knew he wanted to throw caution to the wind, and flurry like a madman, but the energy wasn't there. He did manage to unleash some flurries, however. Campbell too was lagging some, and didn't put the sort of exclamation point on his effort that you might think he should've, being the underdog. At the final bell, one had to applaud the effort; it wasn't quite Vazquez-Marquez, but it was a hard slog, by two willing warriors. At the end of the round, Diaz' left eye was totally closed.

In the eleventh, Campbell kept whacking away at Diaz, whose head was lowered, as he kept his eye pointed towards the floor. It looked like Campbell might stop the Texan, as he landed clean shot after clean shot. But Diaz held on. He lost the round though, 33-89 for Campbell to 14-59 for the ragged Diaz.

In the tenth round, Campbell's energy hadn't flagged yet. He was Diaz-like, pressing the issue, staying in his foes' face. The slick vet, so capable with a shove of his shoulder in tight, and slipping deftly, could smell the upset win. Again Campbell took the stat war: 33-82 to 9-52 for Diaz. Would the judges see what the numbers were saying however?

In the ninth round, again the heads were coming together. Campbell's shots were now harder, clearly, and Diaz looked to be in trouble. No longer the punching machine, Diaz, it was clear, was in the sort of hole he had not experienced to this point. Campbell won the stat war in this round, 43-74 to 16-51.

In the eighth, the action was tight, was else is new? One had to wonder what the judges were seeing. I was seeing tight, tight rounds, that could go either way.

In the seventh round, the cut bothered Diaz. But he did not alter his fighting style; he kept his head down, as did Campbell, and the two kept banging away.

In the sixth round, the pace slowed a tad. Compared to that heavyweight fiasco that tortured us all though it was a mile a minute action. Campbell had a point deducted for a butt, which opened up the slice on Diaz' left eye that much more. The ref then let Diaz' corner touch up the cut. On further review, one could see that a punch exacerbated the damage.

In the fifth round, both men continued the toe to toe tangle. No one chose to jab and move, to this point, but with about a minute left, Campbell started to move more. He moved backwards, and Diaz pursued. Diaz may have stolen the round when he pinned Campbell on the ropes and let loose with seconds to go.

In the fourth round, both men lead, and countered, keeping up the furious pace. Diaz landed well, and Campbell shook his head and told him that it didn't affect him. Campbell scored well with left hooks, and Diaz worked his right hand to good effect.

In the third, Diaz was a bit busier and more accurate, though there was some swelling on Diaz' eye that looked like it could get uglier. The two fighters landed 211 punches through the third round.

The blistering pace continued in the second. Both men were sharp in their punch placement. Campbell found a home for uppercuts here, and looked like a man ten years younger. Will his energy hold up down the line, you had to wonder. Campbell screamed at Diaz after the round, promising he'd be in his face the whole night.

In the first, it was bombs away from the get go.  Both men invested from the start in a body attack. No Klitschko/Ibragimov here, for sure. A butt from Campbell opened a slice over Diaz' left eye.

After the upset, Campbell weighed in: “I knew he couldn’t take it.  I knew I was the bigger puncher.  I could out-box him or out-punch him.  My team and I said all along we saw a lot of hype with Juan Diaz but we didn’t see the substance.  I said I was going to take him out into the deep water and drown him and that’s what I did. I better have won.  I won the last five or six rounds.  I won this for Don King.  I will never disrespect him the way Juan Diaz did.  There’s a tattoo on my back that simply says, ‘fighter’ and that’s what I am and what I proved tonight.”