Don Nelson, the second-winningest coach in NBA history and a five-time champion with the Boston Celtics, passed away on Sunday at the age of 86. His family released a statement saying he died peacefully, surrounded by loved ones, without disclosing the cause of death.

Nelson's impressive career included:

• 250+ wins with three different franchises: Milwaukee, Dallas, and Golden State.
• Three-time Coach of the Year and 18 playoff appearances in 31 seasons.
• Leading the Bucks to the conference finals three times and once with the Mavericks.

He was known for introducing the point forward concept and his up-tempo offense, influenced by his playing days under Celtics' Hall of Famer Red Auerbach. Nelson played 11 of his 14 seasons in Boston, contributing to five championship teams.

After retiring, he began coaching in Milwaukee, where he won seven straight division titles. His time with Golden State was marked by the “Run TMC” era, featuring stars Tim Hardaway, Mitch Richmond, and Chris Mullin. Nelson faced challenges, including a fallout with rookie Chris Webber and a brief stint with the New York Knicks.

He returned to the Mavericks, where he, alongside his son Donnie, played a crucial role in bringing Dirk Nowitzki to the NBA and developing Steve Nash into a superstar.

In 2007, his “We Believe” Warriors famously upset the top-seeded Mavericks in the playoffs. Nelson retired as the NBA's career coaching wins leader with 1,335, a record he held until Gregg Popovich surpassed him in 2022.