The newly-promoted side have shown grit and resolve so far this season, coming from at least a goal down in five of their last six matches and scoring their last 11 goals in the second half of matches.
Di Matteo told reporters: "Last season we won a lot of points in the last 15 minutes of games and we've carried on that way.
"You tell your players never to give up but it's more about instilling it into them on a daily basis.
"It's a philosophy to have and doesn't matter what league you are in."
Di Matteo’s next test is former Chelsea team-mate Mark Hughes’ Fulham, whose only loss so far this season came last weekend.
He said: "Mark and myself roomed together early on at Chelsea. The coaching staff decided 'we'll put this young boy with one of the experienced British lads but communication was a problem.
"I couldn't speak the language then and I don't think Mark's Spanish was very good!
"He's done very well as a manager even though he took the unusual route of starting off in international football with Wales."