Technology giant Apple (NASDAQ:AAPL) is set to report earnings today. Expectations are fairly high, judging by Apple's recent momentum. Apple shares sit atop its 52-week high, and are getting close to the all-time highs reached two years ago.

Apple might have an ace up its sleeve to keep that momentum going. Thanks to its recently formed partnership with telecommunications giant China Mobile Limited (NYSE:CHL), Apple has a fighting chance at producing a beat this quarter, as it did last quarter.

All eyes on China
Apple rallied strongly after second-quarter earnings, in which the company beat estimates on the iPhone. That caused shares of Apple to shoot higher after reporting, since the iPhone is Apple's most important product category. That's why, once again, iPhone sales will be in focus.

But there's reason to be concerned about Apple's iPhone sales when it comes to the United States. Last quarter, Apple produced less than 2% revenue growth in the Americas. This shows the extent that growth in the Americas has leveled off.

By contrast, Apple hit the ball out of the park in the emerging markets, especially in China. Sales in Greater China were up 13% last quarter. China is more important than ever before to Apple. The region makes up one-fifth of its sales, which will only increase further as China sales outperform other geographies like the Americas.

Make no mistake, much of the contribution likely came from China Mobile, and that's what will be in focus when Apple reports on July 22.

Why China Mobile matters so much
Earlier this year, Apple finally closed on its highly anticipated partnership with China Mobile, which is the largest telecom carrier in the world.

China Mobile grew subscribers to 767 million last quarter. Apple will benefit from this in a number of ways. China Mobile is deepening its pool of high-quality customers. For instance, it grew its 3G customer count by 104 million last quarter.

And, even more exciting is that China Mobile's 4G rollout is still in the early stages. China Mobile only received its 4G license last December. And yet, demand is set to be extremely robust. China Mobile has already taken 4G into 16 cities. By February, China Mobile had 29 LTE commercial networks on board. The company vows to become the world's largest 4G network, with 500,000 base stations that will bring service to all cities and key villages by the end of this year

As the rollout progresses, Apple will benefit from data usage among high-quality customers. Data is becoming an increasing driver of China Mobile's performance. Wireless data traffic contributed 18% of China Mobile's total revenue and revenue from wireless data soared 58%. This is a great opportunity for Apple, which can carve a nice slice for itself once China Mobile's customers are firmly in its ecosystem.

The benefits of this partnership are already clear and are just beginning. Going forward, further monetization of these users within the Apple ecosystem -- across other product categories and in its emerging payments platform -- is a major catalyst for sustained future growth.

In all, Apple expects $37 billion in revenue at the midpoint of its forecast. That would represent less than 5% growth year over year. Apple has set a low bar for itself, which presents a strong possibility of a beat.

Keep China in focus
Apple is set to report earnings later today. Expectations are fairly low, based on the fact that Apple is in a muddle-through period right now before it unveils its new products.

That means China's role this quarter is hugely important. Apple has leveled off in recent quarters in developed markets like the United States, and it's likely growth there will be weak again, which is why China will have to step up once again if Apple is going to beat estimates.

China is more important to Apple than ever before, and continued growth there will set Apple up for another great quarter.

Bob Ciura owns shares of Apple. The Motley Fool recommends Apple and China Mobile. The Motley Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.