Schmidt was speaking in Berlin, Germany, trying to explain why it shouldn't be regulated as if it were a gatekeeper of the internet, since other companies like Amazon and Facebook are just as influential.
Google was recently hit with an anti-trust probe in the EU, as critics accuse it of having too much power (its search engine market share is around 90%).
Since many people are likely to go directly to Amazon.com if they're shopping, Schmidt says, it has become a bigger search competitor than Bing or Yahoo.
"Many people think our main competition is Bing or Yahoo. But, really, our biggest search competitor is Amazon," Schmidt says.
Although Schmidt makes the point to show it's not the only "gatekeeper of the internet," Google has meanwhile been ramping up the content of its product listing ads (PLAs), which help make it more attractive for shopping. The more Amazon-like features that Google offers through PLAs - like product descriptions and reviews - the less likely people will be to intuitively start on Amazon, unless they're already loyal Amazon users.
Schmidt also called out Yelp and TripAdvisor, which have complained that Google's de facto monopoly hurts their businesses. Schmidt said their businesses have actually been thriving, according to FT reporters Jeevan Vasagar and Alex Barker.
"The reality is that Google works very differently from other companies that have been called gatekeepers and regulated as such," he says. "?No one is stuck using Google."
Disclosure: Jeff Bezos is an investor in Business Insider through his personal investment company Bezos Expeditions.