The new iPhone 4S may have disappointed reviewers who expected an all-new device, but it's already a huge success among customers, even before it went on sale in stores across the globe Friday.

Apple CEO Tim Cook and his executive team hope the first device launched without Steve Jobs at the helm will safeguard their global market share against a growing challenge from the likes of Samsung.

The company said Monday that it received more than 1 million pre-orders in the first 24 hours after the iPhone 4S went on sale last Friday. This has toppled the previous record of 600,000 set by the iPhone 4 last year. Demand was so high that the Apple Web site said new orders won't ship for a couple of weeks.

It is reported that hundreds of fans queued around city blocks in Sydney and Tokyo Friday to be the first to get their hands on the iPhone 4S.

The iPhone 4S has significant hardware upgrades, though it looks identical to the iPhone 4. It is equipped with an A5 chip, iOS 5, Siri Voice assistant and an 8-megapixel camera along with many features. It is available with a new 2-year contract for $199, $299 and $399 for the 16GB, 32GB and 64GB models of the phone, respectively. The phone is available on AT&T, Sprint and Verizon Wireless.

If Apple sells 25 million iPhones, it will be up by 77 percent from the 14.1 million handsets Apple sold in the September quarter of 2010, when the iPhone 4 debuted.

It appears that the iPhone 4S has taken over the champion attributes from its precursors and is ready to carry on and fortify Apple’s position in the smartphone market. This was much needed for Apple to face the stiff competition from Samsung with smartphones powered by Google's Android software.