Zamora struck a 93rd-minute winner as QPR pipped Derby County to a place in the top flight in what proved a dramatic playoff final back in May.
However, Redknapp, 67, says that he would have called time on his 31-year coaching career had the Rams triumphed at Wembley instead.
"If we hadn't gone up this year I would have turned it in," the veteran manager is quoted as saying by Sky Sports News.
"I would have definitely packed up. I wouldn't have gone back and done another year in the Championship, it didn't appeal to me anymore.
"With 10 minutes to go I was thinking 'what golf club should I join this year - should I play here or there?' and then suddenly Bobby ruined it all."
The West Londoners will mark their return to England's top tier after a year-long absence by hosting Hull City at Loftus Road on August 16.