Robert Guerrero, the two-time featherweight titleholder and junior lightweight titlist, has defeated several notable opponents.
But his next fight, an Aug. 27 date with interim junior welterweight titlist Marcos Maidana, looks as though it will be the toughest of his career.
"I think it the biggest one so far and I think it's the most dangerous one so far, too," Guerrero told ESPN.com on Monday after finding out the fight was signed, sealed and delivered.
Guerrero signed his contract last week and was waiting on Maidana to sign, which he did over the weekend, Golden Boy Promotions CEO Richard Schaefer told ESPN.com.
The fight, which will headline a "Boxing After Dark" card on HBO, will take place at the HP Pavilion -- better known as the Shark Tank -- in San Jose, Calif., not far from Guerrero's hometown of Gilroy, Calif.
"He's a tough guy. He has punching power. He keeps coming and he gets off the canvas when he gets knocked down," said Guerrero, who will move up to junior welterweight for the bout. "When I watch Marcos Maidana fight, I look at the fight and I think the better the opposition in front him, the more he steps up his game."
"Robert is stepping up to face the hardest puncher in the division," Schaefer said. "I really think he belongs on that pound-for-pound list because of what he has accomplished. Maybe if he wins against Maidana that will get him there."
Maidana's last two fights have been all-action slugfests in Las Vegas. In December, he dropped a tight decision to titleholder Amir Khan in the 2010 Boxing Writers Association of America fight of the year. On April 9, Argentina's Maidana (30-2, 27 KOs) narrowly outpointed Mexican great Erik Morales, a former three-division champion, in a grueling brawl.
Guerrero (29-1-1, 18 KOs) fought on the Maidana-Morales HBO PPV undercard and outpointed slugger Michael Katsidis to claim a pair of vacant interim lightweight belts. After his fight, Guerrero said he watched Maidana-Morales on a monitor in his dressing room.
"It was an exciting fight to watch, especially knowing a fight with me and the winner could be made with Golden Boy, and now here it is," Guerrero said. "They both went to war. They put on a great fight and me and Katsidis also put on a great fight. And now the winners, we're clashing in August."
Maidana, who will train in Puerto Rico, confirmed that he had agreed to the fight, tweeting, "I think everybody (will) like the fight vs. Guerrero. I'll prepare myself 100 percent since it's a tough one. But I will win!"
Said Schaefer, "This confirms what we know about Maidana, that he fights anyone, anywhere, anytime. There are very few fighters like that, but he believes in his talents and his skills and in his iron chin and iron will. He feels this will be another big test and he's ready, and it doesn't matter where he's going to take it."
Schaefer has been working on the fight for weeks and was quite pleased that he had closed a difficult deal.
"Sometimes when you make a fight you know on paper going into the fight it has fight of the year written all over it and you know its going to be an action battle. This is one of those fights," Schaefer said. "It can only be a great fight. In the 140-pound division, this is as big as it gets. There many big fights there, but this is certainly one of them.
"This is one I am going to look forward to between now and Aug. 27 until the first bell rings. You'll have people split 50-50 on who is going to win the fight."
Guerrero is anxious to try his hand at a new weight.
"I'm super-excited about the move to 140. Just being at 140, I will be stronger, faster and more well rounded. I'm excited about it," Guerrero said. "Making 140 will be very easy for me. I'm just excited about this fight.
Guerrero said he was also looking forward to fighting at home, where he has good fan support.
"It will be great for the hometown fans. I've been wanting to fight a world title fight in San Jose and it's here. Aug. 27," he said. "I know all the fans are excited about it. I'll stay focused and not get caught up in the hype with all the fans. Just focus and do what I gotta do and everybody is happy."
The winner of the fight looms as a mandatory challenger for the winner of the July 23 (HBO) unification bout between Khan and Zab Judah.
The opening bout of the Maidana-Guerrero broadcast likely will involve Seth Mitchell (22-0-1, 16 KOs), the top American heavyweight prospect. However, he does not yet have an opponent. Schaefer said Chazz Witherspoon (28-2, 20 KOs), whose only defeats have come to top-10 contenders Tony Thompson and Cristobal Arreola, turned down the fight.
Dan Rafael is the boxing writer for ESPN.com. Follow him on Twitter @danrafaelespn.