Jaime Munguia demonstrated during the four-plus months they’ve worked together that he is a better fighter than Freddie Roach realized while watching him from afar.

The International Boxing Hall of Fame trainer has been especially impressed by Munguia’s head movement and overall defensive abilities in sparring sessions. Those are among the attributes Roach wants Munguia to display consistently Saturday night when he battles British southpaw John Ryder in their 12-round super middleweight match in Phoenix.

“He’s better than what I thought, for sure,” Roach told BoxingScene.com. “He’s a more complete fighter and so forth. You know, the comments about what he does well and what he doesn’t do well really doesn’t match up with what he is.”

Munguia’s handlers approached Roach late last summer about replacing former four-division champion Erik Morales as Munguia’s head trainer. The 27-year-old Munguia made some adjustments once they began training together at Roach’s famed Wild Card Boxing Club in Hollywood, California.

“From day one, he’s done a lotta work,” Roach said. “He’s fun to work with. We’ve worked on combinations, changing his style, being more in an attack motion and not a counterpuncher. And he’s doing very well. The first thing I hear about the guy is that he has very, very poor defense.

“And then I said, ‘What are these people talking about? He’s got great offense, and that right there is a good defense.’ It’s not like he goes in there with his hands down and starts swinging with [his opponent]. He’s a good boxer and he has good footwork and his combinations are very, very good. I know that because sometimes he hits me on the chin.”

Munguia (42-0, 33 KOs), who is listed by DraftKings sportsbook as more than a 3-1 favorite over Ryder, will fight for the first time Saturday night since his unforgettable battle with Ukraine’s Sergiy Derevyanchenko 7½ months ago.

Tijuana’s Munguia dropped Derevyanchenko (14-5, 10 KOs) with a body shot in the 12th round, which earned the former WBO junior middleweight champion a unanimous decision on the scorecards June 10 at Toyota Arena in Ontario, California. Had he not scored that knockdown, Munguia would’ve settled for a majority draw in a bout that was voted BoxingScene.com’s “Fight of the Year” for 2023.

Instead, judges Rudy Barragan and Fernando Villarreal scored their fight identically, 114-113 for Munguia. Judge Lou Moret credited Munguia for a slightly wider win, 115-112.

Ryder lost a 12-round unanimous decision to Canelo Alvarez in his most recent fight. A resilient Ryder got up from a fifth-round knockdown and went the distance with boxing’s undisputed super middleweight champion, who won by wide distances on all three scorecards May 6 at Akron Stadium in Zapopan, Mexico.

If Munguia defeats Ryder, he could challenge Alvarez (60-2-2, 39 KOs) in his next fight for the Mexican icon’s IBF, WBA, WBC and WBO 168-pound crowns May 4.

Regardless, Roach expects to coach a better version of Munguia against London’s Ryder (32-6, 18 KOs) than the one that defeated Derevyanchenko.

“I like when he’s busy,” Roach said. “He throws really good combinations, puts ‘em together very well and he has good movement. He’s in and out, side to side, and I think the best thing he’s doing right now is head movement. He has tremendous head movement. He’s making guys miss, miss, miss and making them pay.”

DAZN will stream Munguia-Ryder as the main event of a Golden Boy Promotions card from Footprint Center, the home arena of the NBA’s Phoenix Suns. The streaming service’s main undercard coverage is scheduled to begin at 8 p.m. ET (5 p.m. PT).

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.