LAS VEGAS—In a city that runs on cash, Mike Bloomberg learned that all the money in the world couldn’t save him from an unrelenting pummeling from the 2020 field.

In the grand tradition of a Vegas fight night, Wednesday’s face-off at the Paris Hotel was the most contentious Democratic debate of the 2020 nomination cycle. The six candidates onstage drew sharp-edged contrasts on matters of both policy and personality, with a near-singular focus on newcomer Bloomberg—and with Massachusetts Sen. Elizabeth Warren, who has defined her candidacy around sticking it to the wealthy and well-connected typified by the New York billionaire, leading the charge.

“I’d like to talk about who we’re running against: a billionaire who calls women fat broads and horse-faced lesbians,” Warren said immediately out of the gate, in an exchange that set the tone for the following two hours. “No, I’m not talking about Donald Trump—I’m talking about Michael Bloomberg.”

“Look, I’ll support whoever the Democratic nominee is,” Warren added later.” But understand this: Democrats take a huge risk if we just substitute one arrogant billionaire for another.”

Even though the night started with a round of attacks focused squarely on Bloomberg’s record as mayor of New York, the chippiness quickly spilled over to former South Bend Mayor Pete Buttigieg, who grouped Bloomberg and Vermont Sen. Bernie Sanders together as each too polarizing to win a general election.

Buttigieg warned that Democrats could awake the day after Super Tuesday with Sanders and Bloomberg as the only candidates left standing, who are “the two most polarizing figures on this stage.”

“We shouldn’t have to choose between one candidate who wants to burn this party down and another candidate who wants to buy this party out,” Buttigieg said.

Bloomberg, the billionaire owner of the eponymous financial information and news conglomerate and former mayor-for-life of New York City, became the unofficial target of every other candidate onstage the moment that he qualified for the debate—his first since the Democratic National Committee changed eligibility rules to allow self-funded candidates to participate.

The decision outraged candidates across the ideological spectrum, with Warren, who has made disentangling the American political system from the wealthy and influential the bedrock of her candidacy, using Bloomberg’s entrance as an opportunity to jumpstart her struggling campaign.

Warren was largely an afterthought during the previous debate in New Hampshire and after finishing a distant fourth in the primary she appeared to have lost all momentum.

That changed Wednesday night, as she clashed with Bloomberg over his record with women and nondisclosure agreements, a topic squarely in her wheelhouse of transparency and gender issues.

Bloomberg seemed visibly uncomfortable with Warren’s continued pressing for more information on specific aspects of his treatment of women. At one juncture, she asked the billionaire Democrat how many women were subjected to nondisclosure agreements under his leadership.

“This is not just a question of the mayor’s character,” Warren said. “This is also a question about electability. We are not going to beat Donald Trump with a man who has who knows how many nondisclosure agreements and the drip drip drip of stories of women saying they have been harassed and discriminated against. That’s not what we do as Democrats.”

(Asked after the debate if he felt that Bloomberg—who has a long history of allegedly making inappropriate and offensive comments about women—had adequately prepared for the assault, campaign adviser Howard Wolfson said that while “nobody is perfect,” the former mayor was proud of creating “an inclusive workplace that values everyone.”)

As Bloomberg took hit after hit over his professional conduct, mayoral record, and refusal to release women from nondisclosure agreements, Sanders—who emerged victorious in last week’s New Hampshire primary and appears poised to win Nevada’s upcoming caucuses—emerged from the debate practically unscathed.

“It was a bit of a battle royale,” Wolfson told reporters in the spin room after the debate, although he insisted that Bloomberg had drawn a “clear contrast” between himself and Sanders and added that the contest for the Democratic nomination was a race between the two.

“This is going to be a two-person race,” Wolfson said. “Bernie Sanders in first, Mike Bloomberg in second.”

Short of a tense exchange earlier in the evening with Buttigieg over the perceived extremism of some of his online supporters, the Vermont senator was almost never on the receiving end of the traditional frontrunner treatment.

Bloomberg’s entrance also spelled trouble for other moderate options on stage. A source close to former Vice President Joe Biden told The Daily Beast ahead of Wednesday night’s event that he was “going to be feistier” than in previous debates, with a particular focus on the former New York City mayor, a strategy that he—like nearly every other person onstage—had already previewed in the days leading up to Las Vegas.

But Biden failed to be a chief antagonist for Bloomberg as his campaign struggles to recover after a pair of humiliating lower-tier finishes in the Iowa caucuses and New Hampshire primary largely knocked the wind out of his poll numbers. Biden tried again Wednesday night to focus on the electability argument despite his lack of success in Iowa and New Hampshire, but his performance focused on telling the crowd he was electable rather than showing it.

While the New Hampshire debate may have vaulted Minnesota Sen. Amy Klobuchar to a surprise third place finish in the state, Bloomberg’s debate stage entrance made Klobuchar’s preferred centrist lane more crowded than it had been in months.

The added competition from the former mayor relegated Klobuchar to emphasizing again her credentials as a proven lawmaker as she attacked Bloomberg for “hiding behind his TV ads.” She further had to play clean-up over an earlier failure to name the president of Mexico, giving Warren the chance to show support for Klobuchar in one of the debate’s kinder moments.

Tensions also continued to escalate between Buttigieg and Klobuchar; the Midwestern rivals have little time left to stand out before the crucial Super Tuesday contests.

Before he weathered many of the Democratic field’s constant attacks Wednesday night, Bloomberg tried to win over Democratic voters on one of the issues they care about most: Who can beat President Trump?

Nominating Sanders, Bloomberg said, means another four years of Trump.

“I’m a New Yorker,” Bloomberg said. “I know how to take on an arrogant con man like Donald Trump that comes from New York.”

In a moment that may foreshadow tensions yet to come, the candidates were asked toward the end whether the person with the most delegates should be the nominee even if they come into the convention short of a majority.

“No,” Biden said. “Let the process work its way out.”

And even after getting shredded by his 2020 rivals, Bloomberg couldn’t pass on making one last dig about his financial power in the presidential race where he has already spent hundreds of millions.

“You can join me at mikebloomberg.com too if you want,” the former mayor said shortly before the debate ended. “But I’m not asking for any money.”

—With additional reporting by Hanna Trudo.