SOUTHAMPTON, ENGLAND - MAY 27: Glenn Maxwell of Australia during the ICC Cricket World Cup 2019 Warm Up match between Australia and Sri Lanka at The Hampshire Bowl on May 27, 2019 in Southampton, England. (Photo by Alex Davidson/Getty Images)

Australia's preparation for the T20 World Cup is now complete after a rain-hit no result with England in Canberra on Friday evening, but it hardly feels like it should be.

There are significant questions over the squad who will play the opening match of the Super 12 stage at the World Cup next Saturday evening in Sydney against New Zealand.

The defending champions put together the ideal tournament 12 months ago in the United Arab Emirates, but the pressure of defending that crown on home soil, for the time being at least, looks like it'll be a bridge too far for an Australian team whose form is not anywhere near where it needs to be.

Losing to India 2-1 away from home was one thing, particularly during a series that David Warner and a number of other stars were rested for as they remained at home after a busy start to the summer with six ODIs in quick succession against first Zimbabwe in Townsville and then New Zealand in Cairns.

But the five T20Is back at home against first the West Indies and then England have brought about serious problems with Australia's side.

Captain Aaron Finch's form is one thing - and he didn't help himself on Friday by charging down the wicket first ball of the innings and placing a lofted uncontrolled square drive down the throat of the man at backward point.

We all know Finch has now retired from the ODI arena on the back of a slew of poor performances, and those runs haven't exactly increased in the shortest form of the game, save for a single half-century at number four.

He was, of course, batting at four to allow Cameron Green to get more time at the top of the order after excelling in India where he stood in for David Warner.

Then there are the injury concerns hovering over the World Cup squad which left the need for Green to play the warm-up fixtures, with all of Marcus Stoinis, Mitchell Marsh and Ashton Agar under a cloud.

Green remains on standby for all three, although the deadline for squad changes is now here meaning the selectors must make a final call.

But maybe the player Green should really be on standby for is Glenn Maxwell.

Warner missed out on last night's game with a neck problem, and understandably, the selectors were going to take no chances in aggravating an injury he should recover from in time to play the Black Caps next week.

But instead of playing Green again, the selectors showed their nervousness around the squad by elevating Glenn Maxwell to the top of the order and including Steve Smith.

By all reports - and judging by selections in recent games - Smith is next to no chance of playing in the World Cup opener, but the selectors clearly aren't sold by their own approach given the form struggles up and down the batting order.

Maxwell, coming into Friday night's game, had scored just eight runs in his last T20 innings, and another eight at the top of the order won't do anything to address those concerns.

The move to the top of the order smacked of desperation by the selectors to try and get Maxwell in a different role, and to have him spend some much needed time in the middle.

Maxwell has been backed in by his teammates during the form slump, but there is only so long a team hoping to defend the World Cup crown can afford to keep someone in the team who has virtually been reduced to the role of specialist fielder who can bowl some off-spin.

That's not to say Maxwell's energy isn't an enormous boost to the Australian cricket team, but a World Cup of any description isn't won by an out-of-form team who can't score runs, and right now, Maxwell is the biggest culprit in that department.

Smith's calming influence - he finished not out on Friday - may not suit the high-scoring, big-hitting nature of T20 cricket, but on Australian grounds which are bigger than you'll find in most parts of the world, Smith's game of rotating strike and not facing dot balls is critical.

Take a bundle of big hitters into the tournament and it's a recipe for disaster unless the top three of Warner, Finch and Marsh can get each and every innings off to a cracking start.

Adding Smith at four, who can then float up and down the order based on the situation of the game, seems the way to go, and yet, there has been no obvious candidate to drop out for him.

Right now though, Maxwell seems to be the man.

A lack of runs will put the selectors in a difficult spot, and while he might play against New Zealand in the tournament opener, a lack of runs again or a loss for Australia could see changes begin quickly, because it's clear the selectors are now in panic mode.