Barbarians (6) 11
Try: Collins Pens: Montgomery 2
Australia (13) 18
Tries: Tuqiri, Turner Con: O'Connor Pen: O'Connor 2
Well-organised Australia were relentless in their tackling of Barbarians
Australia's superb defence was the springboard for a hard-fought win over a star-studded Barbarians side in the Olympic Centenary match at Wembley.
The Wallabies withstood strong early pressure for Ryan Cross to create a 12th-minute try for Lote Tuqiri.
Teenage debutant James O'Connor kicked available points but a mistake let Shane Williams set up Jerry Collins for a second-half Barbarians score.
But Australia sealed victory with a brilliant Lachie Turner try late on.
The result means Australia go home having won four of their six tour matches, beating Italy, England and France but losing to New Zealand and Wales.
The match was organised as part of the British Olympic Association's celebrations of the centenary of the first Olympics in London, where the Games will return in four years' time.
Australia took the rugby union gold medal in 1908 with a 32-3 victory over Great Britain, represented by the English county of Cornwall.
In honour of that match, the Barbarians all wore yellow Cornwall socks as they departed from their usual tradition of players wearing their club socks.
In the ninth minute, Springbok wing Bryan Habana, one of seven members of South Africa's World Cup-winning side in the Barbarians' starting XV, broke clear and chipped ahead.
Illustrating Australia's alertness and strength in defence, his kick was fielded near Australia's line by Lote Tuqiri who, despite pressure from New Zealand captain Richie McCaw, grounded the ball for a five-metre scrum.
Minutes later Tuqiri, making his first start since knee surgery after this year's Tri-Nations, opened the scoring after wing Cross burst down the right touchline from deep in his own half and his clever cross-kick inside was gathered up by Tuqiri, who strolled in under the posts.
Full-back O'Connor added the conversion on what was his first start for the Wallabies and the 18-year-old soon stretched Australia's lead to 13-0 with a couple of penalties.
The Barbarians, with South Africa lock Bakkies Botha a powerful presence, did start to gain ground and were rewarded with two penalties from Percy Montgomery - the Springboks' record points scorer.
Habana and All Black wing Joe Rokocoko caught the Wallabies cold with a neat exchange of passes which took the Barbarians to within sight of the try-line, while Samoa prop Census Johnston and Botha both went close with referee Chris White calling on the video referee.
But, with the television pictures proving inconclusive, no try was awarded.
Tuqiri's early try gave Australia crucial momentum on which to build
On the hour, former Australia captain George Gregan came off the Baa-Baas' bench to face his compatriots and, soon after, Australia outside-half Quade Cooper's poor kick out of defence gave possession back to the Barbarians.
Francois Steyn, playing at outside-half, threw a long cut-out pass to Wales wing Williams, on as a half-time replacement for Montgomery, who sprinted clear down the touchline to take several Australians out of the game.
He then put a well-timed pass inside to All Black flanker Collins, who went over for the try, but Steyn missed the conversion and then pushed a penalty wide of the posts with eight minutes left.
Victory was sealed two minutes from time by replacement Turner's breakaway try after Steyn, who missed two goalkicks, was turned over.
Worryingly for Australia, props Matt Dunning, who exited on a stretcher, and Sekope Kepu both went off early in the second-half after the Barbarians demolished a Wallaby scrum.
Barbarians: Percy Montgomery (SA); Joe Rokocoko (NZ), Rico Gear (NZ), Jean de Villiers (SA), Bryan Habana (SA); Francois Steyn (SA), Fourie du Preez (SA); Richie McCaw (NZ), Schalk Burger (SA), Jerry Collins (NZ); Johann Muller (SA), Bakkies Botha (SA); Census Johnston (Sam), John Smit (SA, capt), Federico Pucciariello (Ita).
Replacements used: Rodney Blake (Aus), Shane Williams (Wal), Chris Jack (NZ), Nick Koster (SA) *Uncapped, Ollie Smith (Eng), Mark Regan (Eng), George Gregan (Aus).
Australia: James O'Connor; Lote Tuqiri, Ryan Cross, Adam Ashley-Cooper, Digby Ioane; Quade Cooper, Brett Sheehan; Richard Brown, George Smith (c), Dean Mumm; Hugh McMeniman, Mark Chisholm; Matt Dunning, Tatafu Polota-Nau, Sekope Kepu.
Replacements used: Ben Alexander, Adam Freier, David Pocock, Luke Burgess, Lachie Turner, Drew Mitchell, Peter Kimlin.
Ref: Chris White (RFU)