EXCLUSIVE: The Republican National Committee and the Trump campaign posted their largest online fundraising day ever on Sunday, bringing in $14 million across three entities on the president's birthday — smashing their previous online fundraising record of $10 million on Oct. 19, 2016.

The surge in cash comes as Republicans' war chest continues to dwarf Democrats' holdings, as it has for the entire primary cycle. Trump and the RNC – which have been building a fundraising juggernaut for more than three years – have roughly $255 million cash on hand, compared with the approximately $100 million the Joe Biden campaign and DNC have in their coffers. A competitive primary with numerous candidates on the Democratic side essentially stalled their effort to consolidate donations for months.

The RNC, along with the Trump Make America Great Again Committee (TMAGAC) and Donald J. Trump for President, Inc. (DJTP), received an average online gift of $46, Fox News is told. Trump turned 74 on Sunday.

GOP ENJOYS TWO-TO-ONE CASH ADVANTAGE OVER DEMS, SPENDS BIG ON ADS

“Enthusiasm for President Trump continues to be our greatest motivator and political weapon," RNC Chairwoman Ronna McDaniel told Fox News. "Republicans are thinking smarter digitally and harnessing support and energy for President Trump to up our online fundraising game and outwork, outdo, and outmaneuver the Democrats at every turn."

The largest-ever total 24-hour haul for the campaign was recorded the day Trump launched his reelection campaign last year, bringing in nearly $25 million. The birthday windfall marks the largest online fundraising figure.

The RNC-Trump campaign’s online birthday card campaign for the president received 1 million signatures alone.

"The grassroots support behind President Trump’s re-election is something no campaign has ever seen."
— Trump campaign manager Brad Parscale

Biden continues to lead Trump in most national polling, as well as in key battlegrounds. But Trump has sought to more aggressively head back out on the campaign trail amid the coronavirus pandemic, scheduling his first rally in months this coming weekend.

The former vice president's glitch-prone livestreamed events, meanwhile, have attracted a relatively small number of viewers, and surveys appear to reflect what the president's campaign calls an enthusiasm gap. According to an ABC News/Washington Post poll earlier this year, 53 percent of Trump supporters say they’re “very enthusiastic” about supporting the president, but only 24 percent of those backing Biden say the same about supporting the former vice president.

“The grassroots support behind President Trump’s reelection is something no campaign has ever seen," Trump campaign manager Brad Parscale told Fox News. "Just as more than a million people have registered for tickets to the President’s rally this weekend [in Oklahoma], they are also donating to help his campaign in record numbers. There is an enthusiasm gap - it is real and it is wide. President Trump’s supporters would run through a brick wall to vote for him. Nobody is running through a brick wall for Joe Biden.”

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President Donald Trump speaks during a news conference in the Rose Garden of the White House. Trump will hold his first campaign in several weeks in Tulsa, Okla., next week. (AP Photo/Evan Vucci)

Some Biden supporters have indicated they understand the enthusiasm issue in the race. Fox News reported exclusively last week that top Biden surrogate Terry McAuliffe recently told a videoconference meeting of Virginia Democrats that Biden should remain in his basement -- where he has campaigned remotely during the coronavirus pandemic -- and that Democratic officials are broadly "preferring" that Biden stay out of the limelight.

Fox News obtained a video of McAuliffe's Norfolk comments, which came after Biden has made a series of gaffes in his already-limited public appearances as he social distanced from home — including by declaring that African-Americans who support Trump "ain’t black."

WATCH: TOP DEM SAYS BIDEN SHOULD REMAIN IN BASEMENT

"People say all the time, 'Oh, we got to get the vice president out of the basement,'" McAuliffe told the "monthly breakfast" of the Norfolk City Democratic Committee. "He's fine in the basement. Two people see him a day: his two body people. That's it. Let Trump keep doing what Trump's doing."

Trump, for his part, has dealt with a series of controversies concerning his handling of the unrest following the death of George Floyd, including the decision to clear a park by the White House of protesters ahead of a photo op.

McAuliffe served as campaign chairman for Hillary Clinton's 2016 presidential run. At the Zoom videoconference, he was introduced by a senior Norfolk Democrat, Charlie Stanton, who compared soldiers who participated in the D-Day landing to modern-day Antifa members.

"It's hard for the vice president to break through," McAuliffe told the group. "You've got the COVID crisis. He's not a governor, doesn't have the National Guard. He's not the president, doesn't have the briefing room. He needs to come out strategically. And when he says something like he did on race relations two days ago, it needs to have a big impact -- thoughtful, and that's what we're preferring that he actually do at the time."

But, McAuliffe conceded, "We're building the digital today, which Trump has a huge lead on, he's got like 88 million Twitter followers, so that's a big emphasis for us."

Also on Sunday, Trump Victory, the joint field effort between the RNC and the Trump campaign, celebrated what they called a “summer kick off” with a National Weekend of Action in states across the country.

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Volunteers across the country were coming out to show their support and "celebrate [Trump's] birthday by knocking on doors (in states that allowed) and making phone calls," the RNC said.

Fox News' Paul Steinhauser contributed to this report.