A keenly fought Merseyside derby appeared to be heading for a goalless draw as the final few seconds ticked down at Anfield on Sunday.
There was, however, to be a late twist in the tale as Virgil van Dijk spun a wild volley goalwards and Pickford clawed the ball back into play off his own crossbar.
Origi had not given up on getting a sniff of a chance and was in the right place at the right time to nod into an unguarded net.
Trying to explain the stoppage-time drama, former Liverpool star Redknapp told Sky Sports: “As he’s [Pickford] gone to catch it, he’s caught his hand on the crossbar and knocked it out of his hand.
“Origi has done ever so well. He’s the only one to follow it in.
“It’s a monumental mistake. He looked erratic all game, Jordan Pickford. He never really looked comfortable. That’s a big moment.”
While Pickford had a few nervy moments at Anfield prior to his costly error at the end, it was the performance of the two goalkeepers which had helped to keep the game goalless.
Alisson impressed for Liverpool at the opposite end of the field, and was joined in a stunning on-field celebration by manager Jurgen Klopp as Origi nodded in the most dramatic of winners.
The Belgian striker has become something of a forgotten man for the Reds, having spent time on loan and on the treatment table, but he has netted on derby day before and has stepped back out of the shadows in style.
“I was wondering where he’s been, where he’s gone. What an impact,” said Redknapp.
“It was absolutely incredible. That’s what you want.
“Looking at the game, you’ve got [Mohamed] Salah and [Roberto] Firmino on the bench looking very sorry for themselves and thinking this is going to end up a draw, not a great result for Liverpool and then it goes crazy.”
Victory for Liverpool has ensured that they remain hot on the heels of Premier League leaders Manchester City, with just two points separating two unbeaten sides at the top of the table.