Former Nets assistant Sean Sweeney has been an unsung hero for the Mavericks

BOSTON — As the focus on the Mavericks’ Game 4 dominance understandably went to Luka Doncic, there was an unsung hero, Dereck Lively II, who owned the paint and remains important to any chance of Dallas pulling off a miracle.

And Lively has his own unsung hero, Mavericks top assistant Sean Sweeney.

“I wouldn’t be here without Sweene,” Lively, an all-rookie selection, said, using the nickname for his coach. “Our workouts go back to three days after I was drafted. I couldn’t make a left-hand hook. So just knowing that where I started to where I am now — I wouldn’t be here without Sweene. Pushing me, encouraging me, watching assisted film and understanding how to read the game. He’s always going to be that little devil on the shoulder telling you to go harder. That’s an amazing person to have your back.”

Inside the Mavericks, Sweeney is known as a relentless worker and coordinator of a defense that rated as high as No. 7 the season after his arrival in 2021 — up from No. 21 the year prior.

Around the league, he’s considered among the top assistants and, at 40 years old as of this month, on a head-coaching trajectory.

Jason Kidd understands what’s coming.