Hillary Clinton raised a record $15 million at George Clooney’s $33,000-a-person fundraisers this weekend, but as she dined with some of the nation’s wealthiest donors, her opponent showed off the superior grassroots fundraising power that has propelled his campaign.

Clinton took in the record haul at the two sold-out fundraisers hosted by actor George Clooney and his wife, Amal Clooney, one on Friday in San Francisco and another Saturday in Los Angeles. Combined the events pulled in $15 million, Deadline reported, which stands as the biggest fundraising pull of the 2016 presidential campaign.

“A lot of muscle went into making sure these were out-of-the-ballpark successes,” an insider told Deadline.

In the shadow of Clinton’s big-donor extravaganza in California, Sanders took the chance to highlight the small donations that have set records of their own kind. He countered her fundraisers with an ad titled “$27” that touted the average donation to his campaign.

“If you can’t afford to attend tonight’s event with Secretary Clinton, we invite you to join Bernie’s fundraiser for the low price of turning on your television,” said Jeff Weaver, Sanders’ campaign manager, said in a statement (via Variety).

Bernie Sanders supporters protest George Clooney-hosted Clinton fundraiser in San Francisco https://t.co/MtWSK4CR9G https://t.co/x5TMWoHdWF — ABC News Politics (@ABCPolitics) April 17, 2016

It was quite a contrast to Clinton’s fundraiser, which attracted some of the biggest donors in the Democratic Party and had sky-high price tags. A seat at the head table with Hillary Clinton and the Clooneys ran $353,400, and it was $30,000 just to get in the door. As Deadline noted, the events found a way around traditional fundraising rules by filtering money beyond Clinton’s campaign to other corners of the Democratic Party.

“If those numbers seem high under what is allowed under primary rules, they are — but they also are perfectly within what’s permitted. Like the Sting event and the Radio City Music Hall event of March 2, this weekend’s two Hillary Victory Fund affairs take only the allowed $2,700 per individual or $5,000 a couple directly for the Hillary for America ledger. The rest of the dough is divided up between the Democratic National Committee and state parties from Arkansas to Wyoming for the general election.

While Clinton was dining with ultra-wealthy donors, Bernie Sanders was running the “$27” ad in San Francisco and Los Angeles to counter the events and holding an event of his own. Howard Gold, a Bernie Sanders supporter and founder of the 99 Cents Only Store, hosted the “99% Party,” which cost only $27 per person. The event was held at Gold’s home, which just so happens to be next door to George Clooney.

Clooney's neighbor throwing Sanders fundraiser during Clooney-Clinton event https://t.co/oi88dJAwYN pic.twitter.com/AEPicP1eR7 — The Hill (@thehill) April 16, 2016

Experts say Hillary Clinton’s fundraiser will be an important step for her campaign in California, which is one of the most expensive markets for advertising. It also shows that Clinton is getting serious in her efforts to hold off Bernie Sanders and his grassroots campaign.

“But they are confronting the reality that rival Bernie Sanders is not going away, regardless of what happens in New York and the states that immediately follow,” noted Los Angeles Times reporters Kurtis Lee and Evan Halper. “The well-funded insurgent, whose money comes not in increments of hundreds of thousands of dollars but in tens of dollars from a vast number of donors, has the resources and the determination to inflict considerable pain on Clinton in California.”

The approach seems to be working for Bernie Sanders. He took in $44 million in March, about $15 million more than Hillary Clinton. Despite a lack of big-money donors, Sanders has been able to top Clinton’s fundraising efforts for three consecutive months.

[Photo by JD Pooley/Getty Images]