The famous invitation side scored seven tries, the last of which was converted by France’s longest-serving captain.
Fiji’s Waisea Nyacalevu and Pau prop Chris King scored two tries each, there were further touchdowns for hooker Corey Flynn and Joe Tekori, and Ulster also conceded a penalty try.
A 10,000 strong Kingspan Stadium crowd gave Montpellier-bound scrum half Ruan Pienaar a rousing send off and local favourite Roger Wilson also brought down the curtain on his distinguished spell with the province.
Ulster’s young side showed plenty of promise, too, racing into a 14-0 lead through Stuart McCloskey and Mark Keane with Wilson and Pienaar adding conversions.
Debutant Callum Patterson also touched down but by the interval the Barbarians were 22-21 in front. Former All Blacks hooker Flynn drove over from a lineout, centre Nyacalevu swept over in the corner and King powered over twice from close range.
A rainy night in Belfast didn’t help handling but both sides tried to open up and the Barbarians – fielding at 945kg what might have been the heaviest pack in their history – had the power to open up enough space to work with.
Runners like Tekori, Paul Willemse and Facundo Isa forced their way over the gain line and the pressure told with a penalty try awarded when Ulster were shoved backwards at a five metre scrum.
The extra magic was supplied from an inventive old-school penalty move – the ball switched behind a wall of players – allowing Nayacalevu to score his second.
Then some midfield ingenuity opened up a giant hole which Tekori galloped through from 20 metres out, touching down under the posts to make sure Dusautoir did better than recent Barbarians retirees (Bakkies Botha the most notable) in stroking over the conversion.
Alan O’Connor had scored for Ulster immediately after the break – Paul Marshall creating the opening – and the margin would have been closer if Marshall hadn’t spilled the ball with the line at his mercy inside the last 10 minutes.
The Barbarians missed out on their own chance to add another spectacular try to their scrapbook too.
Alex Goode and David Smith combined electrically down the left on an 80 metre breakout, only for Goode’s strike to be ruled out for a high tackle in the build-up that saw Chris Masoe yellow-carded.
The former All Black – all smiles on the sideline – was one of three more greats bowing out in Belfast with Argentina lock Patricio Albacete and Ireland’s Mike Ross also receiving warm applause from an appreciative crowd.
Ulster: Peter Nelson; Mark Keane, Callum Patterson, Stuart McCloskey, Craig Gilroy; Brett Herron, Ruan Pienaar (joint captain); Andy Warwick, Rob Herring, Rodney Ah You, Alan O’Connor, Peter Browne, Matthew Rea, Clive Ross, Roger Wilson (joint captain).
Barbarians: Alex Goode (Saracens & England); David Smith (Castres), Waisea Nayacalevu (Stade Francais & Fiji), Robbie Fruean (Bath Rugby), Horacio Agulla (Castres & Argentina); Ian Madigan (Bordeaux Begles & Ireland), Rory Kockott (Castres & France); Chris King (Pau), Corey Flynn (Star RFC & New Zealand), Mike Ross (Leinster & Ireland), Paul Willemse (Montpellier), Patricio Albacete (Toulouse & Argentina), Joe Tekori (Toulouse & Samoa), Thierry Dusautoir (Toulouse & France, captain), Facundo Isa (Lyon & Argentina).
Replacements: Richard Hibbard (Gloucester & Wales), Vincent Pelo (La Rochelle & France), Census Johnston (Toulouse & Samoa), Jeremy Thrush (Gloucester & New Zealand), Chris Masoe (Racing & New Zealand), Kahn Fotuali’i (Bath Rugby & Samoa), Brock James (La Rochelle), Jean-Marcellin Buttin (Bordeaux-Begles & France).