NBA's Sam Cassell -- Torn Up Over Flip Saunders ... Gave Me 1st Coaching Job

Emotional moment from ex-NBA star Sam Cassell -- who says he's "torn up" over the death of Flip Saunders ... and will always be grateful to the man who gave him his first shot as a coach.

Back in 2009 -- right after Cassell's playing days came to a close -- Saunders hired Sam as an assistant coach with the Washington Wizards, where he worked for 5 seasons.

Sam's coaching career has continued to blossom since then -- now he's with the Clippers -- and Sunday, Cassell told TMZ Sports he'll always remember the man who gave him his first opportunity.