Preston boss Phil Brown described his decision to introduce substitute winger Danny Mayor was his best ever as a manager.
The 20-year-old, who spent a brief spell on loan at Prenton Park in 2009, netted his first league goal for the Lilywhites when he fired home after 71 minutes to beat Tranmere 2-1.
And Brown, whose side have now won six league games on the spin, admitted Mayor's introduction changed the game.
"That's probably the best substitution I've ever made in my career," said Brown. "When substitutes come on, they have to impact on the game and he did."
Brown added: "I still thought that in the second half they were capable and we needed a third goal. You sometimes need that grinding-out quality and we ground the result out.
"Tranmere are going to be a team at the right end of the division and that's why for me it's a magnificent result, but we didn't start well and I thought the penalty was harsh (on Tranmere)."