Both these countries possess a proud record in the tournament considered the showpiece of their respective sports and are also widely tipped as the teams to beat even when they don`t appear to be in the best of form in the run-up to the mega event.
An unprecedented three Cup titles on the trot (and four altogether) and a fourth successive one beckoning in the tournament commencing at Dhaka on February 19, make Australia stand tall though their aura of invincibility has taken a beating in recent times.
When Ricky Ponting and his men take the field against Zimbabwe at Ahmedabad`s Motera Stadium on February 21 to start their bid for a fourth straight crown, they would go into the Cup history with a phenomenal unbeaten run stretching back to nearly a dozen years.
The four-time champions and six-time finalists were previously beaten in a Cup encounter by Pakistan at Hedgingly, Leeds on May 23, 1999 before they went on to win their second crown on June 20, by avenging that defeat in the summit clash.
After the loss to Pakistan, Australia had won 28 matches and tied one against South Africa (in the 1999 semi-final) and the stupendous run has given them three successive crowns, two of them under the captaincy of Ponting who is now striving for a hat-trick.
Ponting, playing in his fifth successive Cup as the most capped player in the tournament (a 39-match record he shares with his erstwhile teammate Glenn McGrath), is coming off a long finger injury-forced lay-off and missed the ODI series against England.
But the Tasmanian, who was pilloried in the media after Australia surrendered the Ashes to England, is certain to make one last-ditch effort to cling on to the Cup that he has won thrice as a player and twice as captain.
The Australian team for the 2011 tournament looks a far cry from the seemingly invincible ones that he was part of in 1999, under Steve Waugh, and in the next two editions when he led the side.
Australia have a very proud record to defend, not only in the number of title triumphs but also in the number of matches won (51 out of 69 since 1975).
The 6-1 rout of England in the ODI series back home should act as the ideal shot-in-the-arm for the squad which is seeded number one in the 14-side event and are placed in Group A.
The players also have a good idea of what to expect in the sub-continent conditions following regular visits to India in the period after the 2007 Cup and their stints in the Indian Premier League.
Shane Watson is one player who revels in Indian conditions and, in fact, his floundering international career got a mega boost after his show in IPL-I in 2008. He is tipped to be crucial to Australia`s chances with his all-round abilities.
If Michael Hussey is ruled out after being named in the 15-man squad following a hamstring surgery, it will be a big blow to the team`s hopes as the left-handed batsman had adapted brilliantly in the past in the sub-continent wickets.
The new ball attack looks strong with veteran Brett Lee leading it but there`s no McGrath (highest wicket taker in Cup history with 71 scalps) to apply excruciating pressure on the batsmen. There is no Shane Warne too to conjure up his magical tricks with his hustle and bustle.
Absence of a high class frontliner spin bowler could be Australia`s Achilles Heel, especially on sub-continent pitches. But the defending champions would be dismissed by other teams only at their own peril.
Mitchell Johnson would be another key player with the new ball and as a hard-hitting lower order batsman.
"Australia may be blowing hot and cold at the moment but they have an outside chance (to win the tournament)," former skipper Steve Waugh said a few days ago.
Waugh also dismissed suggestions that the Ponting-led side appeared to be weak.
"I don`t think this is a weak Australian side. Australia is still ranked number 1 in the world. In (Shaun) Tait, (Mitchell) Johnson and (Brett) Lee, they have the potential match-winners. The batsmen are also on top. The team has changed. Ricky (Ponting) is coming back from injury."
"Australian players are best when faced with adversity. I don`t think this is a weaker side, just that they are different," Waugh declared.
Australia World Cup team: Ricky Ponting (c), Michael Clarke (vc), Doug Bollinger, Brad Haddin (wk), John Hastings, Nathan Hauritz, David Hussey, Michael Hussey, Mitchell Johnson, Brett Lee, Tim Paine (wk), Steven Smith, Shaun Tait, Shane Watson, Cameron White.
Australia`s preliminary Group A match schedule: v Zimbabwe (Ahmedabad, Feb 21); v New Zealand (Nagpur, Feb 25); v Sri Lanka (Colombo, Mar 5); v Kenya (Bangalore, Mar 13); v Canada (Bangalore, Mar 16); v Pakistan (Colombo, Mar 19).