Clarke's Australia far from the finished article

Australia wrapped up a home series sweep over supine sub-continental opposition for the second season in a row on Sunday but captain Michael Clarke admits they are a work in progress as they embark on their toughest ever year of test cricket.

Fragility in the top order, the retirement of Ricky Ponting and Mike Hussey from the middle order and injuries to the pace bowling unit mean there is plenty to ponder ahead of a tour to India and back-to-back Ashes series.

Clarke, ever the realist, was more than aware that any joy at the 3-0 triumph over Sri Lanka, which Australia secured at the Sydney Cricket Ground on Sunday, had to be tempered by memory of the 1-0 defeat to South Africa that preceded it.

"It probably sums up where we are as a team," he told reporters after the five-wicket victory at the SCG.

"On our good days, we're very good and we can cut it with the best, the number one team in the world, South Africa.

"But on our poor days there's a lot of areas we need to improve, both individually and as a team, so I think what you've seen of the Australian cricket team this summer probably sums up where we're at.

"We're fighting to get better every day, that's the positive. I think we are improving slowly as a group but we know the next 12 months is huge for us.

"We've got a lot of tough cricket in conditions that are generally tough to play in, so we need to keep trying to get better."

The loss of Hussey, who retired after Sunday's victory, will probably be more keenly felt than that of Ponting, who had not been at the peak of his powers for a couple of years.

"I don't think someone will be able to come in and replace him," Clarke said of Hussey.

"He hasn't played as many tests as Ricky Ponting but for the time he's been here he's been unbelievable like Punter was his whole career.

"He's won a lot of games for Australia ... we'll never be able to replace him but what it does do is present an opportunity to somebody else."

Australia could conceivably start the first Ashes test at Trent Bridge in July with a top and middle order in which only Clarke and Phil Hughes have any experience of Ashes cricket.

Shane Watson is the other more experienced batsman likely to play a part but his test season was wrecked by injury and his status further clouded by the continuing debate over whether he is an all-rounder or just a top order batsman.

Before the double-header against England, Australia will first embark on the always tricky trip to India to face a team desperate to show that last year's humiliating 4-0 defeat Down Under was an aberration.

Although Australia's batsmen saw off Sri Lanka's pop-gun pace attack easily enough, the way they struggled sometimes against spinner Rangana Herath did not augur well for the four-test series in February and March.

"It will be really tough, especially in the second innings in the subcontinent, where it is generally very tough to play spin bowling," said Clarke.

"I think we're improving. There are areas we need to continually get better at.

"Spin bowling is probably one of those areas. In a couple of months time we're going to be faced with conditions that do spin a lot so there's no better place to get better than in the subcontinent."

The pace bowling department is in ruder health after test returns for 2009 ICC Cricketer of the Year Mitchell Johnson and Mitchell Starc as well as the emergence of another new talent in Jackson Bird.

Bird was named Man of the Match for the Sydney test and has earned comparisons with Glenn McGrath after taking 11 wickets at an average of 16.18 in his first two tests.

Those comparisons may be premature but the 26-year-old did not look out of place on the test stage and joins young guns Pat Cummins and James Pattinson, who both missed the Sri Lanka series through injury, as a genuine contenders for a test place.

Clarke backed his pace bowlers by naming four against Sri Lanka in the final test and they vindicated his decision by bowling out the tourists twice.

"I'm really happy with the way we finished this summer in regard to the test format and I was really proud of the boys the way we fought it out against the number one test side in the world," said Clarke.

"I think we can take a lot from that series and I think we've shown a lot of improvement this series."