Both GB and Australia have won one and lost one in the International Invitational tournament to set up a mouth-watering contest at the Riverbank Arena (5pm start).
Clarke told the Chronicle: "They lost to Germany so winner takes all in terms of a place in the final.
It's been a while since we beat them but we feel like we're playing well enough to win that game."
He added: "That's the sort of game we want to be in and to be practising for and it could be the sort of game we have to play against them on this pitch in a few months' time so it's perfect practice."
Clarke and his team mates will be sure to receive tremendous backing from the crowd, which may spur them on to victory.
Clarke said: "There's always moments when it's difficult in a game and it's hard work and if there's people willing you on from the side, then it helps."
Earlier in the day, the women's team take on Argentina, who narrowly defeated them in the Champions Trophy final this year.
The women are already assured of a place in Sunday's final thanks to back-to-back wins over Korea and China.
All matches will be shown live on the BBC red button.