Liverpool boss Jurgen Klopp accepted his side needed to change their approach following a testing first half against Everton.
He said the subs came in late but they had the right mindset needed to change the game against a low ranking team on the log which are usually stubborn.
Klopp said he is happy with the impact the three substitutes made to the end result of the game.
"That is what substitutions should do," Klopp said.
The Reds had been frustrated by the visitors in a feisty derby until Andy Robertson broke the deadlock midway through the second half.
The full-back scored after meeting Mohamed Salah’s cross at the back post.
Substitutes Luis Diaz and Divock Origi then combined to seal the win - with the Belgian striker scoring another derby goal against Everton, in what was an inspired double change from Jurgen Klopp.