In iSuppli's accounting, Korean company Samsung was a distant second for the quarter, selling 2.3 million tablets of all types, less than one-seventh as many as Apple, to collect a 9.2% share.

Amazon, Asus and Barnes & Noble rounded out the top 5 sellers, although their combined sales didn't equal Samsung's. Amazon's sales fell 13% quarter-over-quarter, while those by Barnes & Noble, the bookseller that last April over the former's Nook business, plunged 25%.

Apple faces competition from new players -- Google and its , Microsoft and its -- noted Alexander. But she saw no hint that the market leader was backing off what she called its "aggressive strategy."

That strategy will be put to the test next month if, as most analysts expect, . Dubbed the "iPad Mini" by most, the device will reportedly boast a 7.85-in. screen and cost $249 to $299, or $100 to $150 less than the now-discounted iPad 2 from 2011.

It's going to be tough to push Apple out of the top spot, even if it doesn't scale down the iPad.