Shorn of three of their regular back four in Seamus Coleman, John Stones and Leighton Baines, the stand-ins have stepped up and did a good job keeping Liverpool quiet in Sunday's 1-1 draw at Goodison Park.
Tyias Browning, Brendan Galloway and Ramiro Funes Mori had just 17 minutes of derby experience between them - all belonging to Browning - but they helped extend Everton's unbeaten run to seven matches in all competitions.
"Tyias performed with defensive arrogance, Brendan brings a smile to your face and Funes Mori and Phil Jagielka looked like a partnership that had been performing for years," Martinez said.
"Phil Jagielka has been the most consistent and best English centre-back in the last 12 months
It is no coincidence anyone around him performs."
Captain Jagielka is the only Toffees defender to play every minute of every match this season.
He, too, has been pleased with way the replacements have slotted in during an injury crisis.
"We knew with injuries it would be a test for the lads and they tried their hardest," he told evertontv.
"It is all part of their learning curve and fantastic for them.
"It is also great for Ramiro getting this game time and learning the English game."
Funes Mori was signed from Argentinian club River Plate late in the transfer window for £9.5million but his display in the derby showed his quality.
"It has the same intensity as the Superclasico (River Plate v Boca Juniors) back home," he said.
"The fans make it very intense and when they scream you know you are in a derby.
"In Argentina, I played around six or seven derbies so for me I felt normal and it was good.
"Premier League football is very physical and the intensity of the game is high.
"I have to keep adapting to the Premier League, but I really like it and I'm enjoying my moment and I want to keep playing."
Source : PA
Source: PA