The Stamford Bridge clash against the Magpies is arguably more important than Saturday's showpiece, with Di Matteo's number one priority ensuring Chelsea qualify for next season's Champions League.
"We've not talked about it at all," Di Mattteo said of the Liverpool game, insisting he had yet to pick his team for Wembley. "I'm deciding for the game tomorrow. We'll see how the game goes tomorrow and then I'll be thinking about Saturday."
Asked if that meant performances against Newcastle would be taken into account, he said: "Yes. Not just tomorrow.
"I look a little bit more back and look at maybe the last three or four weeks and the way we played and the different players in positions and so on."
It would only be human for players to subconsciously hold back for fear of injuring themselves, but Di Matteo said: "We cannot allow ourselves to think like that and I think we've shown before that we don't do that, in the semi-final against Spurs before the Champions League semi-final, and at Arsenal and so on.
"I don't think that'll be an issue for us. We know how important the game is tomorrow for our club and the players who are going to be playing will be fully committed."
Defenders David Luiz and Gary Cahill will miss the match, both with hamstring injuries, but both were seen running on Tuesday at Chelsea's training ground.
Di Matteo said they will be reassessed again on Thursday and Friday and while it looks unlikely Cahill in particular will be fit for the weekend, Di Matteo was optimistic of both being back before the Champions League final.
He said: "Hopefully, they'll be ready before. I have hope but we don't know yet."