Spurs - who would have gone third in the Barclays Premier League with a victory - went down at Bloomfield Road as Charlie Adam's penalty and further strikes from DJ Campbell and Brett Ormerod rendered Roman Pavlyuchenko's late deflected effort a mere consolation.
"We gave a penalty away under no pressure because of a scandalous challenge and then after that we can't convert chance after chance," Redknapp said.
The result was remarkable not only for the way in which it brought Tottenham back down to earth after their famous Champions League win against AC Milan last week, but also because they had so many opportunities to score over the course of the 90 minutes.
Inaccurate shooting, some superb saves by Seasiders goalkeeper Richard Kingson and several last-ditch clearances all combined to deny Redknapp's men until stoppage time, leaving the 63-year-old fuming.
Redknapp said: "In the second half, it was incredible watching it - missing chances from four or five yards like it was going out of fashion. You expect when you have got good strikers who are goalscorers to stick them in.
"There are balls dropping onto their heads and we are waiting for them to head it into the goal from five yards out and they are not scoring. It was just unreal, but that's just how it goes - full credit to Blackpool, they have done fantastic."
Blackpool are now five points clear of the relegation zone in 12th place and manager Ian Holloway could barely put into words how delighted he was with his team for pulling off what he felt was a richly deserved triumph.
"I don't think there is a word that has been written, printed or ever produced in the dictionary that I can use for how pleased I am," Holloway said.
"I don't think we got what we deserved against Manchester City or Manchester United here and it looked like Tottenham were going to be too good for us, but we got the third goal at an absolutely vital time. I'd like to say thank you to all my lads."
Source: PA
Source: PA