England are on the verge of surrendering the Ashes after suffering heavy losses in Brisbane and Adelaide.
Cook and the rest of his top order have been in poor form during the series, which England trail 2-0.
But the 28-year-old opener said the squad remained as hungry as ever to perform.
"Our confidence has obviously had a hit from the first two Test matches," Cook said on Thursday.
"But as a squad we've made a conscious effort to look forward rather than back.
"We think we've got our preparations right.
"We talked a good game, but it's about making sure we play a good game.
"I don't think it's anything about lifting the players.
"That hunger and desire has always been there in this side.
"We've got another case to show it this week.
"It's a huge honour for me to be joining the 100 club.
"It is a special day. And it will make it a special week if we can produce a performance we know we're capable of."