With an emphatic 5-0 destruction of England in the Ashes in the summer, then a 2-1 series victory away against top-ranked South Africa, few could argue that Michael Clarke's reborn team deserve to be branded the world's best.

It's a stunning turn of events for a side that did not win a single Test match between January and November last year, losing 4-0 in India and 3-0 in England along the way.

Australia also retain their No.1 ranking in one-day international cricket, the first time since December 2008 they have been top dogs in both the Test and ODI formats. They return to the apex of the Test ratings for the first time since August 2009.

After being on top since 2012 the Proteas slip to second due to the ICC's annual update of the rankings, with points from 2010-2011 dropping off the system and the results from 2012 and 2013 losing half their weighting.

“We are incredibly proud to be the number-one ranked team in the world in both Test and ODI cricket, which are two of the team's most important goals,” Clarke said.

“We had a fantastic home summer against England and a great series win away against South Africa earlier this year, but the challenge now is to continue that form.

“We have a huge amount of respect for the South Africa side, and the length it held the number-one Test ranking is testament to the great side it is. South Africa will no doubt continue to be a formidable opponent in Test match cricket."

Cricket Australia chief executive James Sutherland paid tribute to Darren Lehmann's team, which has staged a remarkable turnaround since he took charge only 16 days before the Ashes series began in England last July.

“There has been an enormous amount of hard work and effort on and off the field that has led to this result," Sutherland said.

“However, the true test of a great side is sustained success and now our goal is to maintain these rankings and continue to play great cricket as we lead into challenging Test series against Pakistan and India, and the ICC Cricket World Cup at home.

“Everyone involved with the Australian team - players, coaches and support staff - should be incredibly proud of this achievement,” Sutherland said.

“There has been a huge amount of hard work and effort on and off the field to get to this point and it’s something that those involved with the side should take time to savour."