Addressing a grandiose conference designed to show off Russia's financial resurgence, the new president said that America's "economic egoism" and Western protectionism had triggered a global economic slowdown.
"The aggressive financial policies of the biggest economy in the world have led not only to corporate losses; most people on the planet have become poorer," he told delegates at the St Petersburg Economic Forum.
Western chief executives who came to St Petersburg hoping for hear reassurances from a leader whose liberal credentials have been widely touted instead found a president who often sounded like a clone of his aggressive predecessor, Vladimir Putin.
Slamming the World Bank and the International Monetary Fund for their failure to end the world's problems, Mr Medvedev suggested that Russia should instead take charge of redirecting global economic policy.
He announced that a conference to address major issues like the credit crunch and rising food prices would be held in Russia later this year.
"Russia is a global player and understands its responsibility for the fate of the world," he said.
"We want to participate in setting the new rules of the game."
Just as Russia displayed its military might last month by driving tanks and missile launchers through Red Square for the first time since the Cold War, the forum in St Petersburg was intended as a brash display of the country's newly acquired wealth.
Fleets of black limousines brought Russia's rich to an event that organizers claim could soon supplant the World Economic Forum in Davos.
Roman Abramovich, the oligarch who owns Chelsea Football Club, turned up in one of the world's largest yachts – on which he reportedly entertained Mr Putin, who remains Russia's most powerful man despite taking on the theoretically less powerful position of prime minister last month. Mr Putin did not attend the conference.
World business executives dutifully paid homage to Russia's notoriously sensitive leaders and for the most part avoided words that could upset their hosts.
Yet, for all its confidence, the conference served as a metaphor for the underlying economic weaknesses that the Kremlin likes to claim are either non-existent or not an issue.
Behind the grandeur, the Soviet-era venue that played host to the conference – which replaced a similar forum in London last year after Britain fell out of favour in the Kremlin – creaked badly.
Sound systems wobbled, western executives looked on in occasional bafflement as translation devices periodically failed, some delegates went hungry due to a shortage of food points and security officers behaved at their thuggish worst.
Even the entertainment, provided by Roger Waters, the croaky-voiced former lead singer from Pink Floyd, and the remnants of 1990s one-hit wonders Ace of Base seemed oddly incongruous for a festival with such pretensions of grandeur.
Russia, however, does not like its weaknesses pointed out by foreigners, as Jim O'Neill the respected British chief economist at Goldman Sachs discovered.
Last month, Mr Putin boasted that Russia would overtake Britain as the world's sixth largest economy by the end of the year – a claim queried by the most trusted methods of calculation.
When Mr O'Neill, whose projections on the course of the world economy are internationally respected, predicted that economic growth would begin to slow and that Russia would still be three places behind Britain in 2020, he was greeted with glowers and reproaches from ministers and Russian dignitaries alike.
The World Bank received similarly short shrift when it suggested last week that runaway inflation, which is threatening to undermine Russia's economic miracle, was actually more the fault of the Kremlin's monetary and fiscal policy than of the United States.
The greatest criticism came from foreign oil companies, some of whom have been forced to surrender assets to the state after aggressive and legally dubious campaigns led by the Kremlin.
"There is no confidence in the rule of law in Russia today," said Rex Tillerson, the chief executive of Exxon Mobil.
While delegates found one government ally in the form of first deputy prime minister Igor Shuvalov, rapidly becoming a Western darling for his pro-market views, the big test for the Medvedev government's commitment to property rights is likely to come when the fate of BP's Russia operations is decided in the coming weeks.
BP's 50-50 Russia venture with three Russian oligarchs, TNK-BP, has come under a multi pronged attack in the past few months. Police raids, tax inspections and visa issues for British staff culminated last week in the British head of TNK-BP, Robert Dudley, being summoned for questioning as part of a criminal investigation last week.
Many analysts believe that the state energy juggernaut Gazprom is after a stake in the company and suspect that BP, which gets a quarter of its energy from Russia, will be little more than a bit player in the country by the end of the year.
In one of the conference's many ironies, BP's chief executive Tony Hayward was seated next to his Gazprom counterpart, Alexei Miller.
Mr Hayward, who has consistently praised the Kremlin in the past, avoided questions from journalists by jumping off a stage and running around a conference hall before escaping through a side door.
