But what initially looked like a dramatic development turned out to be nothing more than a technological hiccup.
After the company's report of a complete blockage in China had been relayed by The Associated Press and other media, Google backed off the claim.
The company, based in Mountain View, said its system for tracking Internet access appeared to have misinterpreted what was happening to its search, mobile and advertising services in China.
"It's possible that our machines could overestimate the level of blockage," Google said in a statement. "That seems to be what happened (Thursday) when there was a relatively small blockage. It appears now that users in China are accessing our properties normally."
When the AP initially inquired about the problem in China, a Google spokesman said he had no other details beyond what the company was listing on its own website.
Google began posting daily status updates on the availability of its services in China four months ago. Thursday marked the first time Google has described its search engine as being completely blocked. Other Google services, such as Google's blogging tools and YouTube video site, have been blocked for months.
The company is running the risk of being cut off from the world's most populous country because it is no longer willing to censor search results that China's government considers to be subversive or pornographic.
Google had cooperated with the government's restrictions for four years, but said it had a change of heart after uncovering a computer hacking attack that it traced to China.
Even as it took a moral stand, Google sought to keep a toehold in one of the Internet's most promising markets by automatically shifting search requests from mainland China to its service in Hong Kong, which doesn't fall under the same censorship rules.
But that detour eventually riled China's government, prompting another change that required visitors to Google.cn to click on the page to get to the Hong Kong search engine. That compromise paid off three weeks ago when China's regulators renewed Google's Internet license in the country for another year.
But Google's report of a new barrier in China momentarily raised questions about whether the government had become fed up with the company again.