The one-day world champions were struggling at 65 for six after fine bowling and fielding from Bangladesh with two wickets apiece for Mashrafe Mortaza and Shakib Al Hasan.

Bangladesh, who have lost their last 12 matches in the shortest format of the game, sensed the chance to end that run with what would have been the first major upset of the tournament.

Instead they are eliminated and were left to rue the way they allowed Australia to claw back to a decent total and then surrendered with some poor top order batting.

"I thought we had a very good chance. We should have chased 140 runs," said Tigers' skipper Al Hasan.

"We did not bowl very well in the last four overs, and we played too many shots early in our innings. We need to take the big step forward in these games and start winning some of them," he said.

Bangladesh's excited celebrations of their wickets, cheered by an afternoon Kensington Oval crowd made up largely of schoolchildren, revealed a team that despite that three-year losing streak, truly believed they could beat Michael Clarke's side.

But Hussey and Steven Smith added a vital 74 runs in seven overs to lift the Aussies to 141 for seven.

Hussey bats down at seven in Twenty20 precisely to act as an insurance policy if the big hitters at the top of the order fail.

That can be a thankless task at times with the classy Hussey usually forced to slog in the final few overs but on Wednesday, Australia needed to call on his intelligent and accomplished strokeplay.

"I was just trying to get a partnership going, before the slog in the end overs. Smithy played a good innings and we got up to 140. Thankfully today was my day -- you have plenty of bad days batting lower down, so you got to enjoy the good ones," he said.

Bangladesh knew they had to win with a swift run-rate to qualify for the next stage ahead of Pakistan but they were never really in the running after slumping to 15 for four.

As so often, the impressive Al Hasan provided resistance with a spirited 28 from as many balls before he was caught superbly by Hussey at full stretch on the boundary.

Hussey also caught Mushfiqur Rahim, who had batted with character, off the bowling of his brother David and Bangladesh were bowled out for 114.
 

In the other game Wednesday, South Africa crushed Afghanistan, bowling out the tournament debutants for 80, to win by 59 runs and take their place in the Super Eight stage of the Twenty20 World Cup.

The result eliminates Afghanistan from the tournament but the team representing the war-torn country can take encouragement from an aggressive and enthusiastic bowling display that restricted South Africa to a modest score of 139 for seven.

Graeme Smith (27) and Jacques Kallis (34) provided the backbone to a largely unconvincing South African batting display but their fast bowlers proved far too much for a team making their first appearance in a major tournament.

The result means that none of the un-favoured teams, Zimbabwe, Bangladesh, Ireland or Afghanistan, have advanced from the group stage of the competition.

The Afghan batting display showed a gulf in technique and experience as the top order proved unable to cope with pace, with Morne Morkel taking four wickets in three devastating overs.

At times the Afghan batsmen looked unnerved by the pace and bounce of the Kensington Oval pitch and none of their top seven Afghan batsmen made double figures.

They slumped to 25 for seven before Mirwais Ashraf restored some pride and provided the crowd with some excitement, hitting two sixes in his spirited 23 from 25 balls.

Hamid Hassan, who had earlier bowled superbly taking three wickets for 21 run from his four overs and showed himself to be an accomplished "death bowler" bowling a full length with his in-swing, clobbered two more sixes in his cameo off 22.

The South Africans have little time to reflect on their win — they face New Zealand on Thursday following the opening Super Eight game between England and Pakistan.