For much of the season, Redknapp's men looked capable of challenging for an automatic return to the Premier League at the first time of asking, but a form dip meant the London club had to settle for fourth and a play-off battle.
Many had Derby as favourites going into Saturday's Wembley showpiece and Steve McClaren's side undoubtedly had the better of the match.
However, Derby were made to pay for a failure to capitalise on Gary O'Neil's red card as Bobby Zamora netted the winner two minutes from the end.
Redknapp, though, conceded that Zamora's last-gasp strike came against the run of play.
He told Sky Sports: "No, I would be a lying if I said I could see us scoring. They had 11 men, were probing and Rob Green was making saves. We were hanging on.
"We were hanging on with 10 men. It took a fantastic finish (to win it). We were looking to hang on and maybe get penalties.
"They're a good side, they were getting in gaps. We were hanging on for our lives. Everyone worked hard and we got a fantastic goal to win the game. I couldn't be more pleased.
"That was a one-off. Where do you stand on a touchline, watching a game and hanging in there for a grim death and you go and nick a goal like that.
"That's all I wanted. For these people (the fans) and the owners, who are fantastic people."
Redknapp went on to question whether O'Neil really was the last man when fouling Johnny Russell to earn a straight red card, but he refused to criticise referee Lee Mason.
He added: "I don't think it was the last man. I thought there was a defender behind, but it was a bad challenge, he was going in on goal.
"I wouldn't argue with it, but I thought he'd get a yellow. Then I thought we were bang in trouble, but they (QPR) showed great character and it was amazing."
