Fans can usually rely on Juan Manuel Marquez and Brandon Rios to make for exciting fights, but it takes two to tango and since the old lion and the young slugger aren’t facing each other on the pay-per-view card they share on Saturday, the most entertaining bout on that split-site show could be the scheduled 10-round junior welterweight tilt between Mike Alvarado and Mauricio Herrera.

While the co-headliners take on boxers with stick-and-move styles – Marquez goes for his sixth major title in a fourth division against Sergei Fedchenko in Mexico City, while Rios attempts to regain the WBA lightweight belt he lost on the scales last year against interim holder Richard Abril in Las Vegas – Alvarado, a rugged and aggressive contender, will try to maintain his undefeated record and high ranking against Herrera, a respected fringe contender who is every bit as tough and tenacious as he is.

Both Alvarado and Herrera possess underrated technique and boxing ability but the 31-year-old veterans owe their recent success to iron wills.

Alvarado (32-0, 23 knockouts), of Denver, Colorado, rallied to stop Breidis Prescott in the final round of a fight he was losing handily on the Manny Pacquiao-Marquez pay-per-view undercard last November. Prescott was doing more than outboxing Alvarado, the rangy Colombian puncher was busting up the face of the Thornton, Colorado native.

However, Alvarado continued to advance on his mobile opponent and cut the ring off until Prescott was forced to duke it out in close. Alvarado overwhelmed Prescott with crisp combinations and brute physical strength with a little more than a minute left in the fight.

“I had to dig deep in my last fight,” Alvarado said during a media workout last week. “I was behind on the scorecards and bleeding all over the place, but I found a way to win. I learned a lot about myself.”

Alvarado realized what the people around him – co-trainers Henry Delgado and Shann Vilhauer and promoter, Top Rank – have known for years, that he has the potential to be a world titleholder.

The only thing that has kept Alvarado’s career from taking off is himself. Run-ins with the law have resulted in brief jail stays that kept him out of the ring. The most recent stint (an 18-month sentence that was reduced to about five months when he took part in a boot camp program) cost him a proposed 2009 showdown with Paul Malignaggi when he had spend the second half of that year in jail for violating probation for various offenses.

Alvarado only fought twice in ’09 and 2010 due to his legal troubles, which stemmed from traffic- and driving-related offenses and a domestic violence charge from earlier in the decade, but he bounced back with four fights last year and he insists that his wild days are behind him.

Alvarado put in an intense eight-week camp in Southern California for Herrera, training at the Azteca Boxing Club in Bell, and at Sergio Mora’s gym in Montebello, where he claims the quality sparring has honed his skills to match his vaunted physical strength.

“Fans can expect to see the warrior they saw in the Prescott fight, but with a new skill set,” Alvarado said. “I sparred with Sergio Mora, Alfonso Gomez and (IBF lightweight titleholder) Miguel Vazquez to get ready for this fight. Each boxer had a different style, which helped me up my game.”

Mora, a former WBC 154-pound titleholder who usually fights at middleweight, says Alvarado is a giant for the 140-pound weight class.

“Mike is huge,” Mora said. “He was practically a junior middleweight when we sparred and I could feel his strength. I think I gave him some good work because I’m crafty the way Herrera can be and I tried to get him to move his head more.

“He was kind of stiff and straight up at first. I told him that he needs more fluidity in the ring. He needs to be lighter on his feet and add some rhythm and upper-body movement to his offense. And over the course of about five weeks I saw improvement.”

Alvarado says he’s finally ready to live up to his promise as a pro boxer and a former standout high school athlete. A two-time Colorado state wrestling champ, he was one of the most celebrated high school wrestlers of the greater Denver area in recent decades. The former star of Thornton’s Skyview High School was reportedly unbeaten in prep competition. Alvarado, who credits his strength and steely resolve to his wrestling upbringing, says he compiled a 97-0 record in high school.

Herrera (18-1, 7 KOs), however, isn’t impressed by Alvarado’s stats.

“I don’t care about what he did as a wrestler and I wouldn’t care if his boxing record is 100-0,” said Herrera, who lives and trains in Riverside, Calif. “Records don’t mean s__t.”

Herrera, whose only loss is a controversial eight-round split decision to Mike Anchondo in December of 2009, supported that theory when he outjabbed and outworked ballyhooed prospect Ruslan Provodnikov, then 17-0, to a 12-round unanimous decision last January.

He followed that ESPN2-televised victory with another upset in a Friday Night Fights main event when he outfought Mike Dallas Jr. to a 10-round majority decision last June.

Herrera is not as strong or heavy-handed as Provodnikov or as fast and athletic and Dallas, but he came up with the right mix of sticking and moving and pressure fighting to trouble both prospects. He’s confident that he can do the same thing to Alvarado.

“He’s big and strong like Provodnikov was, but my awkwardness and my jab will frustrate him just like it did Provodnikov,” Herrera said. “The plan is to do a little bit of everything. I’m going to box and move and I’m going to stand and fight. We’ll give him everything and see if he can handle it. I don’t think he can.”

Alvarado begs to differ.

“I’m in the best shape I’ve ever been in,” he said. “I haven’t felt this good in a long time. I hope Herrera is ready to go deep in this fight.”

If Herrera is, this fight – which is underneath the Rios-Abril main event in Las Vegas – just might steal the show on Saturday.