Apple has provided few figures relating to sales of its smartwatches since they first launched in 2015, with industry analysts providing estimates on sales rather than hard facts.
A recent report from technology research firm IDC estimated that Apple sold 1.1 million of its Watch in its first quarter of 2016, a 71% drop from a year earlier.
When the report was published by news agency Reuters, it prompted Apple CEO Tim Cook to challenge the figures.
In an exchange of e-mails, he told Reuters that sales of Apple Watch had rocketed since the launch of its Series 2, and were on track for a record quarter.
“Our data shows that Apple Watch is doing great and looks to be one of the most popular holiday gifts this year,” Cook wrote.
“Sales growth is off the charts. In fact, during the first week of holiday shopping, our sell-through of Apple Watch was greater than any week in the product’s history. And as we expected, we’re on track for the best quarter ever for Apple Watch,” he said, although Mr Cook did not provide figures to support his claim.