TIM Duncan is known as one of the most laid-back players in NBA history.

But the NBA legend turns into a “roaring lion” and a “beast” when he enters the MMA ring, according to his trainer.

Tim Duncan was known as The Big Fundamental for his laid-back attitude
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Tim Duncan was known as The Big Fundamental for his laid-back attitudeCredit: Getty

Duncan with his MMA coach Jason Echols
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Duncan with his MMA coach Jason EcholsCredit: Instagram/jasonecholsfitness

The former San Antonio Spurs has quickly taken to mixed martial arts
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The former San Antonio Spurs has quickly taken to mixed martial artsCredit: Youtube/@echolsfitnesscenter3766

The NBA icon is said to be a 'beast' in the ring
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The NBA icon is said to be a ‘beast’ in the ringCredit: Youtube/@echolsfitnesscenter3766
Jason Echols, of Echols Fitness in San Antonio, has been training with the San Antonio Spurs power forward since 2008.

And videos of the pair training quickly went viral.

Echols says the Hall of Famer was “very hungry” to learn martial arts when they first met.

“His absorption of the martial arts was just phenomenal,” Echols told Bleacher Report.

‘You could really see the athleticism that existed in him already.

“It caught onto these movements, and he was able to absorb them better and pick it up better than the average person because of his athleticism.

“His size…it’s incredible to watch him move.”

What caught Echols most by surprise was Duncan’s aggressive attitude in the ring.

“He’s an animal. It’s a different thing than what you see out on the court,” he added.

“The more intense the training gets, the more calm he becomes, which you’ve seen on the court.

“The way he executes the movements, he’s a f–king monster.”

Echols says Duncan is his No. 1 student “by far.”

He even believes The Big Fundamental “would be a legit competitor” in professional MMA.

“I jokingly said to someone else that it could be a cupcake-baking contest and he would win because he’s just good at whatever he does,” he said.

“The sophistication level of him absorbing the martial arts that we have is very, very high.

“It’s not hard for him to catch up with his capabilities.”