Samsung announced two months ago that its new Galaxy S3 smartphone achieved 10 million sales at the end of July. Since then, the company has claimed to have doubled the figure by reaching 20 million Galaxy S3 sales, 100 days after the handset was launched in May.

The South Korean tech giant said in a statement Thursday that Galaxy S3 achieved the landmark three times and six times faster than Galaxy S and Galaxy S2 respectively. Since 2012, both Galaxy S and Galaxy S2 sold over 50 million units.

According to Samsung, Galaxy S3 sold 6 million units in Europe, 4.5 million in Asia, 4 million in North America and 2.5 million in its home turf of Korea. The company expected the newest Galaxy to exceed the high marks set by its predecessors. As of June, 24 million Galaxy S handsets and 28 million Galaxy S3 handsets had been sold by Samsung, The Verge reported.

Samsung Galaxy S3 achieved the milestone just a week ahead of Apple's next generation iPhone, the so-called "iPhone 5," launch Sept. 12. The new iPhone iteration, considered to be the No. 1 competitor of Galaxy S3, is widely believed to be unveiled at a San Francisco media event next Wednesday.

The rivalry between Apple and Samsung is expected to get even more intense once the new iPhone gets released, given the fact that Samsung's Galaxy S3 outsold Apple's iPhone 4S in August to become the best-selling smartphone in the United States.

However, analysts have predicted that after the release of iPhone 5, this market trend could experience a turn around.

If Piper Jaffray analyst Gene Munster is to be believed, Apple could sell as many as 10 million new iPhone units in the first week of its release, provided the company's suppliers keep up with the pent up demand. Munster also said that September release of the new iPhone could drive the total sales to touch the 28-million mark in the July-September quarter.

According to some other analysts, Apple's iPhone 5 rally could face hurdles due to heightened market competition as many smartphone manufacturers are expected to release new devices with the latest features in coming days. On Wednesday, both Nokia and Motorola held separate press events to introduce new smartphones.

Considering all these, it's pretty clear that Apple's new iPhone will have a tough time ahead when it comes to competing with other rival smartphones available in the market. It would be interesting to see how consumers respond to the Cupertino tech giant's best bet.

Will iPhone be the biggest-selling smartphone so far? Share your thought in the comments section.