Beating Miguel Cotto in Madison Square Garden for the WBO junior middleweight championship could serve as the ultimate achievement for a boxer. Sadam Ali hopes it’s just a stepping stone.

Ali won his first world title in December with a unanimous decision over Cotto, the future Hall of Famer from Puerto Rico. Now, the Brooklyn native and former Olympian makes his first title defense Saturday against Jaime Munguia at Turning Stone Resort Casino in Verona, N.Y. HBO will televise.

Munguia (28-0, 24 KOs) of Mexico took the fight on two weeks’ notice after Liam Smith, Ali’s mandatory challenger, began suffering from a skin condition and had to withdraw from the 154-pound fight.

“It’s a dangerous fight for Ali,” Eric Gomez, the president of Golden Boy Promotions, said of the new matchup. “When you get a guy at the last minute who is a big puncher, you don’t really know what you’re getting yourself into. I actually think it’s a more dangerous fight than Liam Smith. We’ve seen Liam Smith before. We know what he brings to the table. This kid [Munguia] is young, strong and undefeated.”

Munguia was initially considered as a possible replacement for Canelo Alvarez, who was suspended for his May 5 bout against Gennady Golovkin after Alvarez tested positive for a banned substance. But the Nevada Athletic Commission didn’t believe the 21-year-old was experienced enough and wouldn’t sanction the matchup. Golovkin wound up scoring a second-round knockout of Vanes Martirosyan. Ali now enters the ring against an opponent he knows little about.

“There are a lot of differences,” Ali said. “It’s a different style of fighting. But I’ve worked hard in training camp. I just have to adapt and I’ve been doing that all my life.”

Using his speed and surprising power, Ali out-pointed the favored Cotto to capture the title. It was easily the best performance of his career.

“He showed he’s a mature fighter,” Gomez said of Ali. “He wasn’t intimidated. Sometimes you can have a guy who is contender who fights someone like Cotto with his mystique and his name, and sometimes they fold. Ali showed me that he’s a championship-caliber fighter ready to take it to the next level.”

That’s exactly what Ali wants to do: take his career to the next level.

“I showed people I’m not just any fighter,” he said. “Now my goal is to stay champion, keep winning and look great doing it.”