Sen. Elizabeth Warren, D-Mass., landed a resounding political blow on South Bend, Ind., Mayor Pete Buttigieg at the last primary debate over a fundraiser he held at a "wine cave" -- but she's uncorked a backlash ever since due to her own history of lavish events.

Most recently, a new Washington Post report recalled an October 2017 gathering in San Francisco, where she held a luncheon for Senate campaign supporters at Boulevard -- a restaurant that boasts a "wine vault" where patrons can enjoy their meals with wines including a pinot noir that goes for up to $3,800 a bottle.

WARREN'S HISTORY OF FUNDRAISING, CONSULTING HAUNTS BID TO SHAME BUTTIGIEG

The populist senator may have eschewed the "wine vault" end of the establishment, but it's the latest example to indicate her attack has gone sideways. Warren's campaign did not immediately respond to Fox News' inquiry regarding the difference between a wine cave and a wine vault.

"I am frustrated because she said, 'I don't do this. This isn't something I do.' And two years ago she very much did do that, and I was in the room," Warren supporter Chase Williams told the Post. Williams had attended a different pricey fundraiser that same month. This one was in Cleveland, located in what had once been a bank vault.

And as previously reported, the wine flowed at another Warren fundraiser in June 2018 at City Winery Boston. Donors who gave $1,000 to Warren's Senate campaign received souvenir wine bottles, and VIP experiences were offered to those who gave $2,700. Warren’s campaign, responding to that report, noted that “this event, which occurred before the Presidential campaign, was held at a large public music venue with multiple locations throughout the country, not an exclusive wine cave. Their most expensive bottle of wine is $49. As the invite shows, the minimum to get in was $100. It did not require a maxout donation to attend.”

SANDERS CAMPAIGN HITS BUTTIGIEG FOR 'GIMMICK' CONTEST TO LOWER AVERAGE DONATION AMOUNT

Warren, who raised so much money for her Senate campaign that she was able to transfer $10 million towards her 2020 effort, has said she will not engage in these sorts of fundraising efforts for her presidential campaign.

“I’ve said to anyone who wants to donate to me, ‘If you want to donate to me, that’s fine, but don’t come around later expecting to be named ambassador,’ because that’s what goes on in these high-dollar fundraisers,” Warren said at the debate.

Buttigieg took issue with Warren's implication that candidates who benefit from wealthy donors are somehow compromised and pointed to Warren's history as an example.

CLICK HERE TO GET THE FOX NEWS APP

“Your presidential campaign right now as we speak is funded in part by money you transferred having raised it at those exact same big-ticket fundraisers you now denounce,” Buttigieg shot back. “Did it corrupt you, Senator? Of course not.”

As Fox News reported earlier this week, Warren's history of fundraising as well as consulting has complicated her efforts to go over Buttigieg on those fronts. Yet Warren nevertheless has enjoyed a burst of attention over the "wine-cave" attack -- and put Buttigieg on his heels, opening him up to additional scrutiny as well.

Axios reported on Sunday that a top Buttiegieg fundraiser reportedly sent to a prospective donor an email saying “if you want to get on the campaign’s radar now…you can use the link below for donations.”

The prospective donor told Axios that the email was “very telling and concerning.” The fundraiser – H.K. Park – is listed on the Buttigieg website as someone who’s raised at least $25,000 for the campaign.

The report of the unusually blunt suggestion could be a rare look at a campaign possibly offering potential donors a way to buy influence with the candidate.

The Buttigieg campaign, though, said the email did not come from them and they did not authorize the language in it.

Fox News' Brie Stimson and Paul Steinhauser and The Associated Press contributed to this report.