Sen. Kamala Harris (D., Calif.) is trailing entrepreneur Andrew Yang in a new poll of California Democratic primary voters, casting more doubt on whether she is the "top-tier" candidate she claimed to be in July.

Yang, whose signature campaign promise is a universal basic income of $1,000 per month for American adults, touted the Emerson poll's results in a tweet.

"7% in California in 4th place. Must have been the crowdsurfing," he wrote, referring to a viral video of him crowdsurfing with supporters.

The established top trio of Democratic candidates led the California survey, with former Vice President Joe Biden and Sen. Bernie Sanders (I., Vt.) taking 26 percent apiece, and Sen. Elizabeth Warren (D., Mass.) in third with 20 percent.

Harris, however, came in fifth place with just 6 percent support in her home state.

Since enjoying a spike after attacking Biden on his racial record in June, Harris has fallen behind the leaders, stumbling on her consistency with issues and her scrutinized criminal justice record as California's attorney general.

During July's debate on CNN, Rep. Tulsi Gabbard (D., Hawaii) attacked California's record on prosecuting marijuana users during Harris's tenure. Harris fired back after the debate that Gabbard was only attacking her because of poll positioning.

"I'm obviously a top-tier candidate, and so I did expect that I would be on the stage and take hits tonight, because there are a lot of people who [are] trying to make the stage for the next debate," Harris told Anderson Cooper.

The California primary results will be far more significant in the 2020 primary in comparison to previous cycles. A poor showing by Harris there would likely be ruinous for her campaign.

It will take place on March 3, 2020, also known as "Super Tuesday," when by far the most delegates will be up for grabs on any single day. In 2016, the California primary didn't occur until June, when Hillary Clinton and Donald Trump had effectively wrapped up their party's nominations.

Yang announced at Thursday's ABC News debate he would give away $120,000 to 10 Americans over the next year. More than 450,000 signed up for the raffle and many of them donated to his campaign, allowing Yang to raise $1 million in three days.