When it comes to smartphones, Apple is back on top thanks to strong sales around Christmas.The iPhone 5 overtook Samsung’s uber-popular Galaxy S III to become the world’s best-selling smartphone for the first time ever in the fourth quarter of 2012. That’s according to new sales data released by Strategy Analytics.Apple sold an estimated 27.4 million iPhone 5 units worldwide in Q4 — capturing an impressive 13 percent share of all smartphones sold globally."A rich touch-screen design, extensive distribution across dozens of countries, and generous operator subsidies have been among the main causes of the iPhone 5's success," Neil Shah, senior analyst at Strategy Analytics, said in a statement.But the iPhone 5 wasn’t the only Apple device that outsold the Galaxy S III — so did Apple’s older iPhone 4s. Apple sold an estimated 17.4 million of them for an additional eight percent of the global smartphone market — making it the second most popular smartphone."Apple's iPhone 5 and iPhone 4S together accounted for one in five of all smartphones shipped worldwide in Q4 2012," Neil Mawston, executive director at Strategy Analytics, said in a statement. "This was an impressive performance, given the iPhone portfolio's premium pricing."Falling to third place in the smartphone race was the Galaxy S III. The research firm says Samsung sold 15.4 million of the phones in Q4, capturing seven percent of the market share.Though the Galaxy S II has been a huge success for Samsung, its popularity "appears to have peaked," Mr Mawston said."Samsung will surely be keen to introduce its rumoured Galaxy S IV upgrade in the coming weeks to fight back against Apple's popular iPhone range," he added.Samsung is rumoured to be gearing up to launch the Galaxy S IV at an event in New York City on March 14.