So it seems that China has done (or is doing) it. It appears they will become the world's largest economy this year.
It'll likely not be long before we all become acutely aware of this rebalancing of power and since things rarely go well when there is a large shift, let's hope that our new-found interconnectedness will enable this massive change in the world-view of two nations to be peaceful.
On this basis, China’s PPP exchange rate is now higher than economists had previously estimated using data from the previous survey in 2005: a whopping 20% higher. So China, which had been forecast to overtake America in 2019 by the IMF, will be crowned the world's pre-eminent country by the end of this year
http://www.economist.com/blogs/graphicdetail/2014/04/daily-chart-19