Mr Obstfeld said calm had quickly been restored to markets thanks to the "quick" response from the Bank of England and other central banks.
"Clearly central banks were prepared, and markets knew they were prepared," he told reporters on Tuesday.
The UK economy is now expected to expand by 1.8 per cent in 2016, faster than the US, Germany, France and every other G7 economy.
However, the IMF downgraded its forecast for 2017 growth to 1.1 per cent, from 1.3 per cent in July.
Mr Obstfeld noted that the sharp drop in the value of the pound since the Brexit vote had been fuelled in recent days by the Prime Minister's confirmation that the Government will trigger Article 50 and begin formal negotiations to leave the EU in the first quarter of 2017.
Ms May has also hinted that the Government is likely to pull the UK out of the single market, which has also put pressure on the pound
Mr Obstfeld said the drop in the value of sterling would help some sectors such as manufacturing to become "more competitive".
But while he noted that there had been a "resurgence in [surveys] of the tradeable goods sector, the prospect of negotiations would also bring "uncertainty".
He said: "There is some evidence of delayed investments that will have impact in that year."
Recession risks have fallen but recovery remains "precarious"
The IMF said the risk of recession over the next year had fallen across most regions compared with April, including the eurozone, Japan and Latin America.
Government spending measures in Japan had lowered the probability of recession in the world's third largest economy, the Fund said, while the "slightly improved outlook for commodity prices and financial conditions" in Latin America had lowered the risk of recession in the region to less than 40 per cent.
While the IMF believes global growth will pick up in the coming years, it said the "precarious nature of the global recovery" meant low growth could quickly become "self-perpetuating as investment falls, productivity growth declines, labor markets become less dynamic, and human capital erodes".
It warned that unless policymakers took decisive action to boost growth and raise living standards, declining growth rates and concerns about the impact of migration were likely to "contribute to political tensions that block constructive economic reforms and threaten a rollback of trade integration".
Low inflation remains a concern
The risk of global deflation has also declined relative to April, particularly for the US and eurozone as commodity prices start to rise.
While fiscal policies in Japan are expected to lift growth, the probability of deflation has increased, partly due to the recent appreciation of the yen. Japan has been battling low inflation for more than two decades.
The IMF warned that low inflation could also pose a threat to growth and job creation. "An environment of subdued but positive inflation could carry significant economic costs even if a deflation trap is avoided," it said.
Weak investment has dragged down global growth
The IMF said economic growth and investment had grown more slowly than projected in recent years. While employment has grown at a faster pace, the IMF said this pointed to weaker-than-expected productivity growth.
Productivity is a key measure of how much the economy can grow without generating too much inflation. When productivity is sluggish, it means businesses are making less profit.
This usually translates into weaker pay growth and lower living standards.
"Disappointing productivity growth was a main factor behind what proved to be overoptimism in growth forecasts for advanced economies in the period after the crisis," the IMF said.
Growth in emerging markets is crucial
It isn't all doom and gloom. The IMF is pinning its hopes for stronger global growth on emerging markets, which have struggled in recent years with the collapse of the oil price and other commodities.
As countries like China and India become bigger global growth engines, stronger output in these economies will power the recovery forward.
This is expected to drive a third of the expected recovery in growth over the coming years, while the end of recessions in emerging markets such as Argentina, Brazil, Nigeria and Russia will also lift growth.
Advanced economies face several challenges in the coming years, the IMF said.
Protectionism has become a global threat
With Donald Trump in the running to become the next US president, the IMF spelled out the cost of an increase in tit-for-tat trade barriers.
It said the higher cost of traded goods lowers global output by almost 1.75 per cent after five years and by almost 2 per cent in the longer term.
Global consumption would fall by a similar amount, with global investment falling by even more.
Global trade would take the biggest hit, with imports and exports down by 15 per cent after five years and 16 per cent in the long run.
Demographic challenges
Demographic change is set to transform economies in the coming decades.
Population growth is slowing, while the working-age population (between the ages of 15 and 64 years old) is projected to decline over the next five years.
The IMF said these trends would be as common to "old" advanced economies such as the UK, Germany and Japan as "new" advanced economies such as Slovenia and Korea, which are experiencing "a faster and sharper demographic transition".
The IMF said the transition in China, currently the world's most populous country, would be "particularly rapid" with population growth expected to decline to 0.25 per cent over the next five years, from 0.5 per cent in the previous decade.
China's working-age population is projected to start shrinking over the next five years.
An ageing world
The share of workers aged between 55 and 64 years old has increased dramatically in advanced economies over the past two decades.
The IMF said this would "increase pressure on pension and health care systems and worsen debt dynamics, especially as the workforce starts to shrink".
