The Three Lions find themselves on 294-7 and needing to reach a target of 328 runs to avoid the follow-on, but the South Africa-born batsman believes that his side are still in the game.
"I know we're in a spot of bother still but we're 30 behind and if we can bat, just avoid that follow-on and get ourselves back into this game, anything can happen in this fixture still," Pietersen told Sky Sports News.
He added: "[Scoring a Test hundred] is probably one of the best feelings you can have as a cricketer, but it's only a better feeling if it actually contributes something for this team.
"Personal achievements are one thing but this is a team game and if this hundred gets us a draw or gets us a victory at some stage on day five then it'll mean a lot more."
The Aussies declared on 527-7 in their first innings.