The pair traded jabs – most notably on economic policy and gun control – when they took part in the debate. Clinton, in particular, took Sanders to task for his lack of support for harsher gun regulations, especially in the wake of a spate of mass shootings.
"Giving immunity to gunmakers and sellers was a terrible mistake," Clinton said, explaining that she would regulations to prosecute or fine gun makers and sellers in an effort to try "to get makers to make guns safer. To give gun sellers more accountability."
When Sanders explained that he would not pursue holding gun manufacturers and sellers responsible for selling guns to those who later went on to take part in mass shootings – saying that such legislation would end gun manufacturing in America – Clinton took him to task.
"We talk about corporate greed when gun manufacturer sell guns to make as much money as they can make," Clinton said to loud cheers and applause from the audience.
The two candidates also touched on racial issues after being asked what their "racial blind spots" are by CNN host Don Lemon.
Clinton said she wanted to "urge white people to think about what it is like to have the talk with your kids" about the possibility of getting in trouble with police "for no reason." The former secretary of state also referenced support for Sandra Bland, who died while in police custody after a routine traffic stop in Texas in July. Meanwhile, Sanders, who worked as a civil rights activist in the '60s, said that white people in America "don't know what it's like to live in the ghetto."
The politicians also touched on the ongoing Flint water crisis, with both candidates agreeing that Michigan Gov. Rick Snyder should resign or be recalled from office.
While the pair battled it out in the debate, one candidate did emerge victorious – Sanders won the Maine caucuses on Sunday, according to the Associated Press. Sanders walked away with 14 delegates from the caucuses while Clinton nabbed 6.
Despite their clashes during the debate, both candidates shared a laugh at the Republicans' expense. When Clinton asked for people to compare the substance of Sunday's discussion with the GOP debate from last week, Sanders had a quick quip.
"We are going to invest a lot of money in mental health," the Vermont senator said. "And if you watch the Republican debates you know why!"