A clash of the e-commerce titans in Southeast Asia, with Amazon launching its 2-hour express delivery service Prime Now in Singapore on Thursday, putting itself in direct competition with Chinese giant Alibaba for the very first time.

The move to the tiny, but wealthy, the city has been hotly anticipated.

Amazon has largely sidestepped China, but Singapore is seen as a gateway to Southeast Asia’s 600 million people who only do a fraction of their buying online.

Industry experts are bracing for a fierce battle as the two go head-to-head.

Alibaba already has a presence in the region, recently upping its stake in Lazada, an e-commerce firm with a foothold in six Southeast Asian countries.

Analysts expect Amazon to roll out services in major cities across the region in the next six months. But while it has the money and technical knowledge to challenge Alibaba, setting up shop won’t be easy.

As well as various regulatory hurdles, Amazon will have to find a way around logistical barriers, like the huge number of islands that make up the Philippines, or Jakarta’s paralyzing traffic. Not to mention poor internet connections across the region.