Afghanistan recovered from a disastrous start in their World Cup opener against defending champions Australia to post a brave total of 207 in Bristol on Saturday.

Gulbadin Naib, captain of the rank outsiders, took the bold decision to bat in warm conditions in the southwest of England, hoping to amass a score his spin bowlers could defend on the small ground.

But the decision backfired badly, with both openers departing for ducks as Afghanistan slipped to five for two in the second over and looked on course for a humiliation.

Mohammad Shahzad was bowled by Mitchell Starc in the opening over of the match and Hazratullah Zazai quickly followed, caught behind by wicket-keeper Alex Carey off Pat Cummins.

With their team in deep trouble, Rahmat Shah and Hashmatullah Shahidi led a fightback for the minnows, playing in only their second World Cup, putting on a gritty 51 for the third wicket.

Leg-spinner Adam Zampa broke the partnership with a beautifully flighted delivery that brought Shahidi forward and beat the batsman, with wicketkeeper Alex Carey whipping off the bails.

Steve Smith denied Shah a World Cup fifty, taking a catch at short cover off the bowling of Zampa to send him back to the pavilion for 43 off 60 balls.

In the next over, former skipper Smith dived to his left to stop a drive from Mohammad Nabi, returning the ball smartly to Carey, who whipped off the bails with the batsman stranded, leaving Afghanistan struggling at 77-5.

But Najibullah Zadran -- ably assisted by his skipper -- took the fight to his illustrious opponents, smashing 20 runs in four balls off Zampa, including successive sixes.

The big hits brought the knots of Afghan supporters to their feet and a line of flag-waving fans ran along the front of one of the stands.

Zadran brought up his 50 off 46 balls with an edge over the slips off a sharp Starc bouncer. But their momentum was slowed the next ball when Naib top-edged a short delivery form Marcus Stoinis and Carey completed the catch.

Just four balls later another Stoinis short ball dismissed Zadran, with Carey again taking the catch to reduce Afghanistan to 162-7.

Rashid Khan smashed 20 in a Stoinis over to lift the spirits of the Afghan fans and another driven six off Zampa brought up the 200.

But he was lbw to the next ball and the innings ended after 38.2 overs when Mujib Ur Rahman was bowled by Cummins.

As expected, Smith and opener David Warner were both included for their first full major international match since they completed year-long bans imposed after a ball-tampering scandal in South Africa.

Australia will be firm favourites to knock off the runs in the fourth match of a tournament characterised by one-sided contests so far, but Naib will be hoping leg-spin star Rashid can work his magic.

Australia endured a torrid 2018 in ODIs but appear to be peaking at the right time as they chase a sixth World Cup.

They came out on top in their series in India earlier this year before humbling Pakistan 5-0 in the United Arab Emirates.