I don't really believe such thing as 'controlling the world' exists outside the realm of dystopian fiction and conspiracy theories (i.e. inane drivel), and there's a good reason for that: trade relations are easier and more effective than coercion—by far, and most of the Western world has known this for decades with China and the others following suit in the recent times. And since it takes two to trade, assuming both intend to pursue their interests in the process, there will never be a situation where only one side can profit. So as long as the US or any other country mentioned above wants the products made or services rendered in another country for whatever reason (be it price, quality or anything else), you can pretty much forget about them 'controlling' the world. It's all about exchange.
That being said, if you mean control in terms of political or economical influence then the USA-France-Britain-Germany pole still maintains a healthy lead despite all the recent debacles. The only truly major player on the Iran-Russia-China side is, unsurprisingly, China—and its economy lags far behind the US, so technically the US alone would be enough to outperform all three of these countries combined in terms of GDP, and their overall sphere of influence would hardly be comparable. The reason is Iran's and Russia's actual influence doesn't reach far beyond their own borders (despite all the attempts to convince the world otherwise), and at the moment they don't have a lot to offer besides their natural resources, whereas the US does well to put its fingers in every pie—to the extent that the US dollar is the world's currency standard and English is the de facto international language of choice. I am, in fact, writing this answer on a computer which is almost entirely designed by American companies, running an American operating system, via the international communication network developed in the USA. Need I say more?