Victory with a lesson to learn is like gold to a trainer.

So even though Ireland’s Callum Walsh had the Madison Square Garden Theater crowd on its feet following his ninth-round stoppage Friday night, Freddie Roach savored the thought that he can keep pressing his promising junior-middleweight to improve.

“He didn’t fight his best fight. We need to be a lot better in training camp. I definitely know that [after tonight]. And that starts tomorrow,” Roach told BoxingScene minutes after the 23-year-old Walsh improved to 10-0 with his eighth knockout triumph. 

Walsh’s defeat of Kazakhstan’s Dauren Yeleussinov (11-4-1) will further boost the profile of the top-15-rated fighter (WBC, IBF) who’s promoted by Tom Loeffler and backed by UFC President Dana White.

Roach took pleasure in seeing Walsh land defining blows in the first half of the bout, but he was hoping for more of the scoring flurries than his fighter produced to end the bout.

“I was happy with the outcome,” the Hall of Fame trainer said. “He finally put his combinations together.”

Roach remains supremely confident in Walsh, knowing his next foes will likely occupy spots in the rankings beyond where the Irishman sits now.

“There’s a lot of guys out there – a lot of good fighters – and whoever they give us, I’m not going to turn them down, that’s for sure,” Roach said.

Among the top 154-pound fighters in the world are champions Tim Tszyu (WBO) and Israil Madrimov (WBA) while Jermell Charlo is a champion in recess and top-10 entrants Serhii Bohachuk and Sebastian Fundora are headed to a March 30 showdown in Las Vegas.

The best thing Roach took from the night was the same thought that thrilled the revelers in attendance who were headed out to start a long St. Patrick’s Day weekend in New York City.

“[Walsh] finished well, figured out those combinations that didn’t go so well for him at the beginning of the fight, and it worked well for him,” Roach said.

The veteran trainer, best known for cornering Manny Pacquiao, now heads back to his Southern California gym to begin camp in earnest with unbeaten former 154-pound champion Jaime Munguia of Tijuana, who meets undisputed super-middleweight champion Canelo Alvarez May 4 at T-Mobile Arena in Las Vegas.

Roach said he’s thrilled to participate in such a global event.

“Been a great time [lately] because I’ve got Munguia, a great young fighter who works his ass off every day even though he’s already been a champion,” Roach said. “Great worker. He comes into spar three days a week and he’ll spar with anyone in the gym.”

Munguia and Alvarez will host a news conference Tuesday in Beverly Hills.