Blues boss Di Matteo repeated his mantra from last season's stunning upset of Barcelona ahead of Wednesday night's crunch showdown at Stamford Bridge.
The Italian had already billed the Group E game with Shakhtar as Chelsea's biggest since they were crowned kings of Europe, and he was under no illusions about the task facing his side against opponents who completely outplayed them in the reverse fixture two weeks ago.
Admitting it was time his players played like European champions after taking just four points from their opening three matches, Di Matteo said: "We need to be at our best. We need a perfect game tomorrow [Wednesday] night. Every individual player going on the pitch has to perform at the highest of their ability.
"It's important we start well and get the crowd behind us and draw confidence from a good start."