Paul Pierce is opening up on the most terrifying experience of his life … revealing his near-fatal stabbing in 2000 shaped him into the man he is today.

The Celtics legend reflected on his past in an emotional conversation on Monday night’s episode of Fox’s celebrity competition show, “Stars On Mars” … explaining the Boston nightclub incident — in which he was stabbed 11 times — completely changed his point of view.

“I’ve showed endurance in my life because I never gave up,” Pierce said in the clip. “I kept going and going.”

The Truth added he was at the “lowest point in my life” when he got in the altercation … saying, “I was like 23 years old, living my dream, and then all of a sudden I’m fighting death.”

But, instead of letting the stabbing derail his journey, Pierce said it made him want to work even harder.

“Not only was it a low point, it was a high point for me, too. It changed my thinking, it changed my mindset, it changed how I lived.”

Pierce compared the stabbing to his experience on the show … as he spent the first few days struggling to gain any ground, but persisted and made it to the very end.

“It’s kinda been my life, starting at the bottom and rising up.”

Pierce went on to play every game of the 2000-01 season … eventually bringing a championship to the Celtics in 2008.

Pierce has a chance to get a similar result on the season finale, which airs at 8/7c.