Tim Cook demolishes anyone who thinks Apple is about to get smoked by Chinese upstarts like Xiaomi

Apple is on top of the world.

iPhone sales are through the roof, so profits are soaring, and Android is faltering ever so slightly.

And yet, many people still see Apple as vulnerable. Much of Apple's future growth depends on iPhone sales in countries like China and India, where Apple's phones cost almost as much as a month's salary for workers.

In China, in particular, some people think Apple will ultimately be flattened by Xiaomi, a young smartphone company that's on fire.

Speaking today at a Goldman Sachs technology conference, CEO Tim Cook said he's doesn't worry about Xiaomi any more than he worries about any other major competitor.

Cook said, "We've always had stiff competition. We always will have stiff competition, this will make us better."

Xiaomi is only four years old, but it's already the biggest smartphone seller in China. That's vaulted it to a $45 billion valuation from private investors, making it the most valuable startup in the world.

Xiaomi started off as a company that cloned Apple. Its founder, Lei Jun, dressed like Steve Jobs. Jun held big events that mimicked Apple's style, even down to saying "one more thing..."

The company has a cult following in China. It sells phones using a flash-sales model where people buy them online in short bursts. The phones sell out quickly.

But Xiaomi is different than Apple in a key way: It sells Android-based phones at half the price of an iPhone.

As a result of its meteoric rise, some people think it's only a matter of time before Apple is shoved aside and Xiaomi takes over China, and then, later, the world.

Cook didn't have much to say about Xiaomi in particular, but he noted that Apple has always had tough competition. When Apple started selling iPhones it had to beat Nokia and BlackBerry, two established companies. And then, Samsung came on strong. In the PC industry, it fought Dell, IBM, and many others.

Cook says Apple will not "lose sleep over" Xiaomi. Apple's just going to focus on making the best products in the world, and Cook believes the rest will take care of itself.

Right now, it's pretty much impossible to question Cook. Apple has taken shots from the biggest, brightest companies in the world, and it's the most valuable company in the world. Today, it became the first company to close with a market value over $700 billion.

Is Xiaomi a risk to Apple? Of course. But, so was Samsung, and Nokia, and Dell, and everyone else. Apple has done just fine for itself.