Singles' day was 11/11 so it should be in there, no?
I wonder if that's because Alibaba is mostly a marketplace and they sold $25B worth of stuff with a margin of 5-10% on it, meaning they'd only have generated ~1-5B for themselves on that day.
Alibaba has a different business model than Amazon, more similar to eBay actually. Alibaba takes a small cut on sales from third parties who do all the work. That small cut is what gets reported as revenue, despite sales figures of many times that.
Amazon only counts the revenue they make from third party sales in the actual transaction cost (small percentage of sale price). Alibaba counts everything even though they give most back to the vendor. They're very different numbers.
You're comparing two completely different figures.