For more than 20 years, NBA fans, and Warriors fans in particular, have come to regard Don Nelson as a sort of offensive mad scientist as a head coach.

So it was refreshing to hear the Comcast Sports Net roundtable discussion after the Warriors’ season opener on Wednesday night. Greg Papa was host, and Gary St. Jean (former Warriors executive and coach and longtime Nelson assistant), Dave Del Grande (online sportswriter) and Matt Steinmetz (longtime NBA beat writer and current color TV analyst on Warriors games).

St. Jean pointed out that during Nelson’s first 12 years as an NBA coach, all with the Milwaukee Bucks (including seven straight division titles), he not only emphasized defense but was considered a defensive innovator, expanding on strategies he learned as a player under Red Auerbach.

It was a fascinating, enlightening discussion. St. Jean said Nelson became “enamored” with speed and offense when he first came to the Warriors more than 20 years ago.

Steinmetz pointed out that Nelson is a master at what he has to work with — if he had big, tough defenders, you would see the Warriors play better defense. But since they don’t, we don’t.

Intriguing discussion.