The last time an unknown undefeated KO artist from Argentina debuted on HBO, Walter Matthysse hung tough with Paul Williams for as long as he could in a wild scrap before being overwhelmed by the emerging American fighter in the 10th round.

Matthysse, 25-0 with 24 knockouts at the time, only lived up to some of his hype. He was as game and heavy handed as billed, but that’s about it. Matthysse, who lost four of his next five bouts by stoppage — including a Knockout of the Year candidate to Kermit Cintron — showed little in the way of skill, stamina or ring generalship.

What will the next hyped Argentine prospect show HBO’s American audience? Fight fans will find out on Nov. 6 when Matthysse’s younger brother Lucas takes on Zab Judah in a Boxing After Dark main event from the Prudential Center in Newark, N.J.

The set up to Lucas Matthysse’s showdown with the former welterweight champ is ironically similar to the one his older brother faced almost 4¾ years ago. He’s an undefeated but unknown puncher from Argentina making his HBO debut against a very talented American southpaw.

However, that’s where the similarities end, according to Eric Gomez, head matchmaker of Golden Boy Promotions, which briefly promoted Walter Matthysse and recently signed Lucas Matthysse.

“They are very, very different fighters,” Gomez told RingTV.com. “This kid (Lucas) can box as well as punch. He doesn’t just stand and trade. He’ll take a step back, he uses angles, and he takes a good punch. He’s a 180-degree turn from his brother. He’s the best prospect out of Argentina right now, in my opinion.”

What Gomez says about Matthysse might be true but the best prospect from anywhere could be in over his head against the resurgent Judah, who returned to the 140-pound division with an impressive third-round stoppage of Jose Armando Santa Cruz in July.

Judah (39-6, 27 KOs) appeared to recapture the form that made him a two-time junior welterweight titleholder in dispatching the former lightweight contender with a frighteningly powerful left uppercut and a furious follow-up combination.

Matthysse (27-0, 25 KOs) is aware of the danger the veteran Brooklyn native, who is only 32, posses.

“I’m prepared for a tough fight,” Matthysse told RingTV.com through translator Cicilio Flores, who co-operates the World Crown Sports gym in Oxnard Calif., where the 28-year-old Argentine has set up camp with middleweight champ and countryman Sergio Martinez. “I am always well prepared for my fights, but for this fight I’m training like it’s my last fight. This is the most important fight of my career.”

Matthysse seems to understand that it’s not often a fighter gets the chance to make a statement to the boxing world and significantly advance his career in one high-profile fight.

He says he learned from watching his older brother’s setbacks that a fighter must be 100-percent prepared in order to make the most of big opportunities such as the one he’s receiving against Judah.

“Walter had a lot of distractions in his life before he fought Williams,” Matthysse said. “He didn’t train properly. He didn’t have the best people around him at the time, and I don’t think he had a strong camp. I didn’t travel with him to the fight, but I watched it live on TV in Argentina, and it bummed me out to see him lose.

“But his loss taught me the importance of having good team around you and having a full training camp to prepare you for your fights.”

Gomez heard about Matthysse’s strong work ethic from the fighter’s Argentina-based promoter Mario Arano. The matchmaker has watched Matthysse closely since witnessing the fighter score a first-round KO of Dominican prospect Ramon Duran on the undercard of a Telefutura show at the MGM Grand in Las Vegas the night before the Oscar De La Hoya-Floyd Mayweather Jr. fight in May of 2007.

“His promoter in Argentina always told us that Lucas was better than Walter,” Gomez said. “I kept my eye on him and brought him back to the States against Rogelio Castaneda Jr. in 2008. He looked good but the fight ended in a no-contest in the third round because of an accidental headbutt.

“Arano kept pushing for us to sign him, so in late 2009, I put him in camp with Shane Mosley when Shane was still preparing to fight Andre Berto. Within a week, Shane and Naazim (Richardson) were raving about Lucas. So Oscar and I drove up to Big Bear to see Lucas spar with Shane in person.

“Oscar’s jaw dropped when he saw what that kid was doing to Shane. He was catching Shane with big punches, backing him up and working him over with body shots against the ropes. He forced Shane to box. After the sparring, Shane told us ‘He’s the one who should be fighting Berto.'”

Sam Garcia, co-trainer of junior lightweight prospect Eloy Perez, was at Mosley’s Big Bear gym the day De La Hoya and Gomez paid a visit. The young trainer, who also watched Matthysse spar with Perez and lightweight prospect Karl Dargan during that camp, said he became an instant fan of the Argentine boxer-puncher.

“He’s brutal,” Garcia said. “That’s the best way to describe Lucas Matthysse. It doesn’t matter who he’s sparring with — Shane Mosley, Eloy Perez or Karl Dargan — it’s always something worth watching. Every time he landed, there was a thud. There’s accuracy and power in every punch he throws — hooks, right hands and especially body shots. His left to the body is probably his best punch.

“Whoever trains him is doing a good job because he was in great shape and ready to spar with anybody from his first day in camp, which is something you don’t often see in Big Bear. Even elite boxers need a few days to get used to the high altitude but not Matthysse. He’s one of those guys who rolls out of bed and is ready to fight. He’s a nice guy, but he’s all business in the gym.”

Adam Flores, who co-operates the World Crown Boxing gym with his brother Silvio, also used the phrase “all business” when describing Matthysse.

“He’s a super committed person,” Flores said. “I’ve never seen such focus in the gym. He concentrates 100 percent on whatever it is front of him.”

On Nov. 6, Judah, with all his vaunted speed and power, is what will be in front of Matthysse.

Despite Matthysse’s sparkling record and Judah’s history of folding in big fights, many fans and boxing writers favor the more-experienced fighter to prevail, which is just what Gomez wants people to think.

“I wanted Zab as an opponent for Lucas,” he said. “I started beating the drums for this fight back in April. I hounded HBO until Kerry Davis finally said OK. The fact that Zab is dangerous is precisely why he’s the perfect opponent for Lucas to make his name against in America.

“Can Lucas lose this fight? Of course. Zab can hurt anyone for the first four rounds of a fight. I’m a little bit worried, but Matthysse and his team wanted a dangerous opponent. So they got one. But this is a dangerous fight for Zab as well. I think this kid is the real deal. This kid can hurt him. He can knockout Zab. If the fight goes past four rounds, it’s over for Zab.”

If Gomez’s prediction comes true, it will be the beginning for Matthysse. The fighter will have not only made a bold statement to a wide U.S. audience but also to a deep and talented division.

“There are many names in the junior welterweight division, too many to mention,” Matthysse said. “I’m not one of those names right now, but after this fight, everyone will know who Lucas Matthysse is. I think they will like what they see.

“I have a lot of heart. My style is similar to those of the best Mexican fighters. I like to go to the body and I put a lot of pressure on my opponents. I want to test myself against all the names of the division.”

If he beats Judah in impressive fashion, fans will take to Matthysse and no doubt clamor for showdowns against Tim Bradley, Amir Khan, Devon Alexander and Victor Ortiz.

For now, however, the only name that matters to Matthysse is his own. He wants the Judah fight to erase the image American fans of his brother’s high-profile losses.

“This fight isn’t just for me,” said Matthysse, whose entire family — including his mother — is composed of former boxers. “It’s for the Matthysses. It’s for our family honor. I have to clean up our reputation a little bit, and it starts on Nov. 6.”