35-year old lightweight champion Juan Manuel Marquez successfully defended his lineal title and picked up three (WBA, WBO, IBO) alphabet trinkets by stopping 25-year old Juan Diaz in the ninth round of a thrilling, all-action contest in Diaz's hometown of Houston.

The younger Diaz (34-2, 17 KO) started hot and was winning most of the early rounds on sheer volume and pressure, but was getting tagged here and there by the cagey, highly skilled Marquez, too. It was a cut that undid Diaz after Marquez started seizing the momentum.

Cut early in the eighth round, Diaz's body language and expression changed almost immediately. It was a bad cut right outside his right eye, with the blood dripping into his line of vision. But you cannot discount that in two fights where he's been cut, he has quickly lost full control of the fight and been unable to keep himself going.

The first time around, Nate Campbell wore him down for the rest of the bout and handed Diaz his first career loss in March 2008. Almost a year later, loss number two comes at the hands of Marquez after another cut. Marquez dropped Diaz midway through the ninth, then put him away mere moments later.

Nate Campbell is a really good fighter. Juan Manuel Marquez is a great fighter on his way to the Hall of Fame. Marquez (50-4-1, 37 KO) smelled the blood and took Diaz apart.

I'm not saying Diaz is gutless, and I thought HBO's Max Kellerman posing the question of, "Did you not learn anything from the Campbell fight?" was at best poorly worded and at worst hack broadcast journalism. I am saying he has twice seemed to hit the panic button when cut now. It was a question coming into this fight; for me, Diaz's heart was the biggest question.

He again showed he is a hell of a good fighter when the going isn't too tough. But how much resilience does the young man really have? Right now, he's starting to build a legacy of not being able to win tough fights. I'm not disrespecting Juan Diaz, simply calling it like I see it. He's been firmly tested twice, had his gut checked, and lost hard both times.

Marquez called out Floyd Mayweather Jr. after the fight, saying that since Manny Pacquiao doesn't want to fight him he wants to fight Floyd. It's not realistic. Bob Arum recently said that Floyd wanted $20 million to fight Shane Mosley, and if he can't get it there, he certainly can't get it for Marquez.

On the televised undercard, WBA featherweight titlist Chris John (42-0-2, 22 KO) retained his title on a 114-114 draw across the cards against Houston's Rocky Juarez (28-4-1, 20 KO). The fight was far better than most of us expected, with both of them fight at a crisp pace. I had John winning 115-113, and I truly feel he won the bout. He vastly outlanded Juarez, who snuck in some rounds on good power punching, particularly late in the fight when the drama got high and it felt like the Houston crowd might will Juarez into a stunning knockout of John.

Rocky also fought arguably his best fight ever, maybe even better than the first go-'round with Barrera. But it was clear at most points that John is simply a better boxer than he is. If they rematched, I think John would probably win wide. This was a good, competitive fight. But so, too, was Barrera-Juarez. The rematch saw Barrera pick Rocky apart for 12 rounds.

The only thing wrong with John-Juarez was Texas referee Laurence Cole, who's assured of being involved in at least one major fight on any multi-fight, big card run in Texas. He's awful, and he was awful again tonight. There are referees that have bad nights, but I don't remember a single time Cole ever had a good one. How Texas continues to put up with this guy and his intrusive, absurd tactics is beyond me. Cole is the worst referee in America.

All in all, the HBO show tonight was just fantastic. Marquez-Diaz is an early Fight of the Year candidate, and John-Juarez set the stage beautifully. All four fighters came to impress tonight, and they all did.

The Houston fans turned out for their fighters, too. Jim Lampley reported early in the telecast that the show had turned in the biggest live gate ever for boxing in the state of Texas.