Age has not eroded the skills of lightweight champ Juan Manuel Marquez (left), who locked eyes with familiar challenger Juan Diaz following their weigh-in on Friday. Contrary to the observations of some fans and media Diaz has plenty of fight left at age 26. He plans to prove it during his rematch with Marquez on Saturday in Las Vegas. Photo / Naoki Fukuda

JUAN MANUEL MARQUEZ vs. JUAN DIAZ

When: Saturday, July 31

Where: Las Vegas

TV: HBO Pay-per-view, 6 p.m. PT / 9 pm. ET

Weight: Lightweight (135 pounds)

Title(s) at stake: Marquez’s RING magazine championship (and WBA and WBO titles)

Also on the card: Daniel Jacobs vs. Dmitry Pirog, 12 rounds, for vacant WBO middleweight title; Robert Guerrero vs. Joel Casamayor, 10 rounds, junior welterweights; Sakio Bika vs. Jean Paul Mendy, 12 rounds, super middleweights; Jorge Linares vs. Rocky Juarez, 10 rounds, lightweights.

MARQUEZ

The essentials

Age: 36

Height / Reach: 5-7 (170cm) / 67 (170cm)

Hometown: Mexico City, Mexico

Turned pro: 1993

Record: 50-5-1 (37 knockouts)

Trainer: Ignacio “Nacho” Beristain

Fight-by-fight: http://boxrec.com/list_bouts.php?human_id=12222&cat=boxer

The Ring rating: Lightweight world champion

Titles: IBF featherweight (2003-05; was stripped of title); WBA featherweight (2003-05; was stripped of title); WBO interim featherweight (2006; vacated to move up in weight); WBC super featherweight (2007-08; lost title to Manny Pacquiao); THE RING world lightweight title (2008-present).

Biggest victories: Marco Antonio Barrera, March 17, 2007, UD 12 (to win WBC super featherweight title); Joel Casamayor, Sept. 13, 2008, TKO 11 (to win THE RING world lightweight title); Juan Diaz, Feb. 28, 2009, TKO 9.

Worst losses / draw: Freddy Norwood, Sept. 11, 1999, UD 12 (for Norwood’s WBA featherweight title); Manny Pacquiao, May 8, 2004, draw 12; Chris John, March 4, 2006, UD 12 (for John’s WBA featherweight title); Pacquiao, March 15, 2008, SD 12 (lost junior lightweight title); Floyd Mayweather Jr., Sept. 19, 2009, UD 12.

DIAZ

The essentials

Age: 26

Height / reach: 5-6 (168cm) / 67 (170cm)

Stance: Orthodox

Hometown: Houston, Texas

Nickname: Baby Bull

Turned pro: 2000

Record: 35-3 (17 knockouts)

Trainer: Ronnie Shields

Fight-by-fight: http://boxrec.com/list_bouts.php?human_id=29486&cat=boxer

The Ring rating: None

Titles: WBA lightweight (2004-08; lost it to Nate Campbell); WBO lightweight (2007-08; lost it to Campbell); IBF lightweight (2007-08; lost it to Campbell).

Biggest victories: Acelino Freitas, April 28, 2007, RTD 8 (for Freitas’s WBO lightweight title); Julio Diaz, Oct. 13, 2007, TKO 9 (for Diaz’s IBF lightweight title); Michael Katsidis, Sept. 6, 2008, SD 12; Paullie Malignaggi, Aug. 22, 2009, UD 12.

HEAD TO HEAD

Losses: Nate Campbell, March 8, 2008, SD 12 (for his WBA, WBO, and IBF lightweight titles); Juan Manuel Marquez, Feb. 28, 2009, TKO 9; Paulie Malignaggi, Dec. 12, 2009, UD 12.

HEAD-TO-HEAD

Skills: No disrespect to Diaz but apart from Floyd Mayweather Jr. and Ivan Calderon there are no better pure boxers in the sport right now who can execute as well as Marquez does. Even at 36, the Mexico City veteran is a textbook technician-counter puncher whose timing and accuracy make his combination punching a thing of beauty and brutality. Diaz, who exhibits a quick educated jab and decent lateral movement when he wants to, is an underrated boxer but he still takes a backseat to Marquez.
Edge: Marquez

Power: Neither fighter is defined by his power. Marquez is known as a technician. Diaz is a pressure fighter. However, the older man’s superior technique — the proper leverage he gets on his punches and the correct manner in which he turns his shots over — translates into superior power, especially when he puts his punches together. Marquez, a natural featherweight, was the first (and only) fighter to stop Joel Casamayor and Diaz, and he did so because of his excellent punching form. Diaz has scored some impressive stoppages too (Acelino Freitas and Julio Diaz stand out), but he did so with volume and pressure. He forced both vets to quit on their stool. He didn’t drop them or score clean knockouts.
Edge: Marquez

Speed and athletic ability: Because of his pudgy appearance, Diaz is often written off as a mediocre athlete, a boxer who has excelled because of his work ethic. However, while he is a classic overachiever, he’s also a deceptively quick and agile fighter. His early title defenses against then-undefeated Jose Cotto (27-0) and ultra-rugged Fernando Angulo were not the result of relentless pressure, but rather fast combinations and nimble footwork backed by hair-trigger reflexes. Marquez has a better-looking physique but he’s not faster or necessarily more explosive than Diaz.
Edge: Diaz

Defense: Diaz can be a defensive-minded boxer who stays on the outside of his opponent’s reach when he puts his mind to it as his split-decision over Michael Katsidis proved, however, his heart and youthful aggression often get the better of his common sense as his losses to Nate Campbell and Marquez illustrate. Marquez is not that hard to find with punches but he edges Diaz in this category because of his superior form and his ability to remain poised and stay within his gameplan.
Edge: Marquez

Experience: Diaz has tremendous pro seasoning for a 26-year-old fighter but just about everyone save for Mayweather, Manny Pacquiao, Bernard Hopkins and Shane Mosley have to defer Marquez, a veteran of 56 pro bouts who has been world-class since 1997, in the experience department. Despite being blatantly avoided for much of his career, Marquez has faced 11 titleholders/champs. Diaz, who has faced seven titleholders, is no slouch but he’s not in Marquez’s league.
Edge: Marquez

Chin: Marquez has been down (four times versus Pacquiao, once against Freddy Norwood, and once against Mayweather) but he’s never been stopped in more than 50 pro bouts. Diaz has been down against lesser fighters (much lesser), including Ubaldo Hernandez and Eleazar Contreras Jr. ‘Nuff said.
Edge: Marquez

Conditioning: Both fighters lead Spartan lifestyles, enjoy training hard in the gym and are extremely dedicated to the sport. Diaz has gone the 12-round distance eight times without stamina issues. Marquez has fought the 12-round distance 12 times in his hall-of-fame career and has never faded in the late rounds.
Edge: Even

Wear and tear: The common thought is that Diaz is on the downside of his career because he’s 2-3 in his last five bouts. Some say his aggressive, full-tilt style has helped lead to early burnout, and these observers might be correct. However, that doesn’t mean that Diaz has more wear and tear than Marquez, a 17-year vet. Apart from his losses to Campbel and Marquez, Diaz hasn’t absorbed many beatings in his 10-year career. Marquez has been in some grueling contests late in his career, including his victory over Diaz. Because of the dramatic ending, many fans forget about the punishment the vet took over the first half of the bout. The hotly contested 24 rounds he went with Pacquiao, plus his bloody shootouts with the lesser-known likes of Terdsak Kokietgym (AKA Terdsak Jandaeng) and Jimrex Jaca, have to have taken a toll on his 36-year-old body. His recent welterweight venture with Mayweather didn’t do his body any favors, either.
Edge: Diaz

Corner: Marquez’s longtime coach Nacho Beristain has been called Mexico’s greatest active trainer and is respected as one of the best in the world. His resume, which includes tenures with a dozen renown former titleholders, merits that distinction. However, Diaz’s trainer Ronnie Shields has trained and worked the corners of just as many notable fighters, many of whom are in the hall of fame (or will be). And Shields, who is quite a few years younger than Beristain, appears to be coming into his own as a trainer, while the veteran coach may have seen better days.
Edge: Even

Outcome: Both fighters will begin this rematch with the respect that was earned in their thrilling first bout. It won’t start fast but it won’t take long for it to heat up. Diaz will work behind his jab more consistently in this fight than he did last February and his lateral movement will limit their exchanges and Marquez’s ability to counter punch him, but by the middle rounds of the bout the veteran champion will begin to cut the ring off and land right hands over Diaz’s jab. The moment Diaz is rocked by one of Marquez’s well-timed right-hand bombs the boxing match will end and the fight will begin. As he did in the early rounds of the first bout, Diaz will find that he’s able to push Marquez back on his heels and land left hooks when he charges forward. Marquez will absorb punishment but he’ll keep his composure and fire back with uppercuts from both hands and hooks of his own. The two lightweights will trade power shots through the late rounds of the bout, but Marquez will land the harder and more accurate punches.

Prediction: Marquez by close unanimous decision.

Michael Rosenthal contributed to this feature.