Amazon (AAPL) had a one-time shot to loosen Apple’s (AAPL) hold on the worldwide tablet market, and it grabbed a 14% share last quarter according to a report issued Thursday by IHS’s iSuppli.

Although the iPad managed to hold on to a 57% share, that was down from 64% in Q3 and less than IHS had projected.

Apple customers were tempted by “shiny new alternatives,” says IHS senior manager Rhoda Alexander. According to her research, however, the primary alternative was not the Fire, but the iPhone 4S.

By the time Christmas sales were over, Apple had shipped more than 15.4 million iPads and Amazon nearly 3.9 million Kindle Fires, passing the Samsung’s Galaxy Tab and Barnes & Noble’s (BKS) Nook to take the No. 2 spot in global sales.

But Alexander adds a big caveat:

“The long-term viability of the [Fire] will hinge on the success of Amazon’s business gamble, which depends on tablet sales driving substantial new online merchandise sales at Amazon.com in order to attain profitability.”

Meanwhile Apple pulled in more than $9 billion in Pad revenue while the introduction of so-called “value-priced tablets” (i.e. the Fire and Nook) created what iSuppli called “chaos across the Android tablet marketplace,” forcing competitors to clear inventory at fire-sale prices.

And with the anticipated launch of the iPad 3 in the next few weeks, iSuppli expects Apple to take back in Q1 2012 whatever market share it lost in Q4 2011.

Below: iSuppli’s spreadsheet.