"I got relegated with Blackburn,” he told TeamTalk.
“I'm not sure how many of the other lads in the dressing room have, but it's not a nice feeling to have. It was the lowest point of my career.
"I don't want it to happen again, so I will be doing everything I can, and I'm sure the other lads will as well to keep us up."
Newcastle face local rivals Middlesbrough in a crunch relegation battle at St. James' Park on Monday night, with the loser of the clash almost certain to fall through the trap door into the Football League.
And Duff has called on the club's passionate support to get behind the team.
“This game is huge and we are going to need all of the fans right behind us again," he said.
"It doesn't come much bigger for me personally, it's one of the biggest games I have been involved with in my whole career."
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