Apple's (NASDAQ:AAPL) iPhone X has now been on sale for over two months as Apple works to achieve supply-demand balance. The company had a strong holiday shopping season, based on robust App Store spending and activation figures. Investors will have to wait until Feb. 1 for the company to report fiscal first-quarter earnings, at which time Apple will share exactly how many iPhones it shipped during the December quarter.

There's now some evidence that the iPhone X sold extremely well in at least three key markets.

iPhone X lineup

Image source: Apple.

Survey says

Kantar Worldpanel ComTech has released its latest estimates on numerous smartphone markets for the three months ending November 2017, which would only include just under a month of iPhone X availability. Despite limited availability, the iPhone X enjoyed "stellar" performance in Great Britain, China, and Japan, according to Kantar.

In the U.K., Apple's new flagship was the best-selling smartphone in November, overtaking Samsung for the top spot and grabbing its highest market share in three years. iPhone X was also the best-selling smartphone in Japan for the month, while the iPhone 8 was the No. 2 best-selling model.

While meaningful markets, those two still are far behind China in terms of importance. Kantar's Dominic Sunnebo said, "Apple was riding on the back of some momentum before the iPhone X release but demand for latest model in urban China has been staggering given its price point." Within urban China in November, iPhone X was the best-selling smartphone model. Much of this demand is coming from customers switching from local brands, including Huawei and Xiaomi.

It's worth pointing out that Apple didn't necessarily do that well for the entire three-month period measured: iOS market share fell by 4.2 percentage points in Great Britain and 5.5 percentage points in Japan, while growing 4.6 percentage points in urban China. But considering how much pent-up demand there was for iPhone X that inevitably led to some purchase delays, combined with short iPhone X supply for the first couple of months, investors shouldn't be too concerned. iPhone X supply has improved dramatically since the end of November.

Bouncing back in the Middle Kingdom

The iPhone X's strong performance in China is especially important, as Apple is finally bouncing back after a couple of years of middling performance. Revenue in its "Greater China" geography returned to growth in the September quarter, with sales jumping 12% to $9.8 billion, and that was before iPhone X started shipping.

The Chinese market is more sensitive to new form factors, and iPhone X is off to a strong start that should help the Mac maker maintain -- or even accelerate -- its momentum in the largest smartphone market in the world.

Evan Niu, CFA owns shares of Apple. The Motley Fool owns shares of and recommends Apple. The Motley Fool has the following options: long January 2020 $150 calls on Apple and short January 2020 $155 calls on Apple. The Motley Fool has a disclosure policy.