Matt Hayden made 22 (Getty Images).

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Australia retained their unbeaten World Cup with a comprehensive -run victory over Sri Lanka in their Super Six clash at Centurion Park.

The Aussie batsmen raced to 319 for off their 50 overs.

Then Brett Lee put Australia on course for the World Cup semi-finals with another destructive spell of raw pace to remove Sri Lanka's top order.

And though Aravinda de Silva responded with an entertaining 90, Sri Lanka never recovered.

Lee's explosive new ball burst helped reduce Sri Lanka to 48 for four in reply to Australia's commanding 319 for five and he also sent captain Sanath Jayasuriya to hospital after he was hit on the left arm by another short delivery.

He claimed three wickets in 11 balls while Sri Lanka lost four in 22 balls to put Australia firmly on course for the victory which virtually guarantees their participation in the semi-finals.

Experienced campaigner Aravinda de Silva at least provided some resistance to Australia's attack, hitting an unbeaten 23 and forging a 49-run partnership with Kumar Sangakkara which guided their side to 97 for four at the halfway stage of their reply.

It took only 12 balls of Sri Lanka's innings for Lee to make an impact, hitting Jayasuriya as he attempted to defend another short delivery and after several minutes treatment on the pitch he was led away to hospital for an x-ray with the prospects of his ability to bat again in the match looking bleak.

It was a costly blow for Sri Lanka, who lost fellow opener Marvan Atapattu eight overs later when he attempted to drive back down the pitch but Lee took an excellent return catch diving to his left.

Lee struck again in his next over to remove the out-of-form Mahela Jayawardene, who lasted only three deliveries before edging tamely behind to wicketkeeper Gilchrist having scored only 16 runs in four previous innings in the tournament.

Just to emphasise Australia's dominance, Glenn McGrath struck in the next over to remove Hashan Tillekeratne, who was bowled with a full-length delivery after he had battled to reach 21 having replaced Jayasuriya.

Fiery fast bowler Lee made a further breakthrough in the very next over when he trapped Russel Arnold leg before with a full-length delivery to finish with three for 25 from his brilliant eight over new ball spell.

Australia's massive total was achieved after two outstanding innings from Gilchrist and Ponting as the world champions set out to achieve their 13th successive win in one-day internationals.

Gilchrist set the tone with a typically flamboyant 99 off 88 deliveries, which included two sixes and 14 other boundaries, and looked destined to claim his first century of the tournament, particularly after he was dropped by Muttiah Muralitharan on 96 after he had cut Chaminda Vaas.

But captain Ponting, looking for a second run after he had driven Muralitharan into the deep, did not anticipate Vaas' superb direct throw which hit the stumps at the non-striker's end and denied Gilchrist his hundred.

Ponting tried to match his team-mate's extravagant strokeplay and hit 20 off one over from Vaas, which included two sixes as Australia began to accelerate towards the end of their innings.

Ponting's superb display was ended with five overs remaining when he mis-timed an attempted pull off Dilhara Fernando and wicketkeeper Kumar Sangakkara took a running catch after he had scored 114 from 109 balls.

Australia lost two more wickets in their pursuit of quick runs with Damien Martyn's well-paced 52 from 58 balls being halted when he was bowled by Fernando attempting a big heave in the final over while Darren Lehmann pulled straight to mid-wicket.