England had thrashed India by nine wickets in Brisbane, before notching up a comfortable three-wicket win at WACA yesterday to make it to the finals.
"It's gone pretty well. I think we've developed a lot the last few months, throughout the Sri Lanka series and now under Eoin Morgan's captaincy in Australia. I think we can be pleased in the direction we're going," Buttler said today.
"I think the performances we put in have been good. In Hobart we got close, we should have got more runs and put more pressure on them but Australia bowled pretty well at the end. But it was a tight game so we've been getting closer and hopefully tomorrow will be third time lucky."
This clash will be a proper dress-rehearsal for England and Australia as the two sides will clash again in their opening World Cup encounter on February 14 in Melbourne.
"Tomorrow's a big game for us and we're desperate to put in a big performance against a much-fancied Australia side. It'll be another good marker of where we're at as a team and how far we've come," he added.
Asked if England are going into the World Cup as underdogs, Buttler said, "It's never the worst place to be and our recent form over the last 12 months wouldn't suggest we'd be anything else either. But we've got into a pattern where we're starting to build confidence as a side and we've started to put in performances where we feel they're good enough to win games of cricket going into a World Cup.
