A TMNT-inspired nickname, and why Callum Smith has bragging rights over Canelo Alvarez

Callum Smith, above, faces Canelo Alvarez in super middleweight unification fight on Saturday. Alex Livesey/Getty Images

Callum Smith is scheduled to make a third defense of his WBA super middleweight world title against Canelo Alvarez on Saturday, confident of his ability to pull off arguably the biggest upset in boxing this year. But who is the 30-year-old from Liverpool, England, trying to put a dent in the Mexican superstar at the Alamodome in San Antonio?

Winning the World Boxing Super Series 168-pound tournament in 2019 was one his greatest achievements in boxing, but there are few other things that should know about "Mundo" Smith.

1. Fighting family

Callum (27-0, 19 KOs) comes from a family of boxing brothers, just like his opponent on Saturday. One of Callum's three elder brothers, Liam (29-2-1, 16 KOs), lost his WBO junior middleweight world title to Alvarez in 2016. Canelo (53-1-2, 36 KOs) stopped Liam with a wicked body shot, and Callum was ringside to see it.

Liam Smith won the race between the brothers to win a world title. In an attempt to win back the same belt, Smith was outpointed by Jaime Munguia in 2018. Liam, 32, most recently boxed in December 2019, earning a decision win over Roberto Garcia in Phoenix.

Eldest sibling Paul Smith (38-7, 22 KOs), now retired at 38, lost three world title attempts at super middleweight, against Arthur Abraham (twice) and Tyron Zeuge. He was also stopped by Andre Ward in 2015.

Stephen Smith (28-4, 15 KOs), 35, was outpointed in two world junior lightweight title bids in 2016, to Jason Sosa and Jose Pedraza, and then suffered a sickening tear on his left ear against Francisco Vargas in a technical decision loss a year later. Stephen's most recent outing was in November 2019, a decision victory over Jonny Phillips.

"It's not pressure having three older brothers all in the same job as me -- it's a help," Callum Smith told ESPN three years ago.

"People say I look like an older fighter in a young man's shoes and it feels like I've been around the game for ages. I've been able to get lots of advice off my brothers and learn through their experiences."

2. Mum can't watch

Callum might come from a boxing-obsessed family, but his mother, Margaret, cannot stand to watch any of her sons in action from ringside. Instead, she goes for a walk or a drive, watches television or plays bingo.

"She still goes to the bingo and turns the phone off when I fight or one of the others," Callum said. "She just asks, 'How is he? How's his face?' when she's contacted after the fight.

"When we all retire it will be the happiest day of her life. She's proud of what we've all done but she doesn't enjoy it. Most mums of boxers only have one to worry about -- but she's got four."

Callum's brothers and dad have traveled to the U.S. with him for the Alvarez fight.

3. Raising awareness

Callum -- along with Paul, Stephen and Liam -- has had the word "autism" across his fight shorts to raise awareness about the developmental disorder.

"My younger sister Hollie has autism, which is why we have 'autism' on our shorts," Callum told ESPN in 2017. "She was diagnosed with autism at age 2. All our reactions at the time were, 'What was that?' More people have become aware of it in recent years, but back then they weren't ...

"We wear 'autism' on our shorts to raise awareness and show support for other families dealing with autism. We're helping to do our part, we raise money for autistic schools. It's a full-time job for my mum and dad. [My sister] is unbelievable but there are good days and bad days. Some days she laughs and is smiling, but others she's hard work and doesn't sleep through the night. It's tough for my mum and dad then, and a lot of other families go through something similar."

4. Crowning moment

Smith became world champion by stopping English rival George Groves thousands of miles from the pair's home nation.

Smith earned most of the $10 million purse from winning in the first world title fight ever staged in Saudi Arabia.

Smith lifted the WBA super middleweight title with a seventh round win in the final of the World Boxing Super Series -- an eight-man elimination tournament -- after sending Groves tottering backward from a left hook and then left him on his knees after a vicious assault that included a right hand to the body.

Smith made a first defense, a third-round stoppage of Hassan N'Dam, on the undercard of Anthony Joshua-Andy Ruiz Jr. 1 at Madison Square Garden in New York, before winning a unanimous but disputed decision over another English rival, John Ryder, on Nov. 23, 2019, in Liverpool.

5. Rocky moment

Alvarez has been in the ring with some of the best fighters in the world: Floyd Mayweather Jr., Gennadiy Golovkin, Miguel Cotto and Shane Mosley. Smith can't compete with that résumé, but he does have a better knockout ratio than Canelo (70% to 64%) and physical advantages which, combined, could make this a treacherous assignment for Alvarez.

And if you want to compare their one common opponent, Smith did a quicker job. Alvarez stepped up from middleweight to beat Smith's fellow Liverpool-based boxer Rocky Fielding in three rounds two years ago. However, Smith managed to beat Fielding quicker, in 2 minutes, 45 seconds of the first round five years ago. Smith's demolition of Fielding is one of 10 first-round knockout wins in his professional career, which he launched after failing to qualify for the 2012 London Olympics.

Smith, who is seven inches taller than Alvarez and has a 7½-inch reach advantage, has fought at super middleweight since turning professional in 2012, but this will be only Alvarez's second fight at 168 pounds.

6. What does his nickname mean?

Callum Smith's nickname is "Mundo" -- not because it means "world" in Spanish but due to a childhood obsession with the Teenage Mutant Ninja Turtles.

"I was obsessed with the Turtles," Smith said. "There's Leonardo, Donatello, Michelangelo and Raphael, and my dad [Paul Sr.] used to call me Callemundo, and said I was the fifth turtle."