Apple Watch shipments beat expectations, topping 18 million in 2017, up by more than 54% on 2016, according to Canalys.

The Series 3 was the key growth driver, as total shipments of the latest version of Apple's Watch were just under 9 million, making up nearly half of all shipments in 2017, the research firm said.

Apple's Q4 performance was impressive in itself, as shipments grew by more than 32% over Q4 2016 to 8 million, the highest ever number of shipments in a single quarter, not just for Apple, but for any wearable vendor.

"The cellular version of the Apple Watch was in strong demand in the US, Japan and Australia, where all major operators stocked it in time for the holiday season," said Vincent Thielke, Research Analyst at Canalys. The Apple Watch Series 3 is the fastest-selling LTE wearable on the market, with shipments doubling quarter on quarter to reach 1.6 million. "But limited operator selection in the UK, Germany and France influenced consumer purchase decisions, and stifled the growth potential of the connected Apple Watch. Moving into new markets, such as Singapore and Hong Kong in Q1 2018, just in time for Chinese New Year, is a good move," added Thielke.

Apple continues to focus on its core iPhone user base. Its recent updates to the Series 3, such as GymKit and Apple Heart Study, are proving to offer compelling use cases, obviously encouraging users to spend more on accessories.