A day after saying she didn't plan to make an endorsement in the Democratic presidential race, Hillary Clinton effectively backed former Vice President Joe Biden during an appearance on The Tonight Show on Wednesday.

Clinton, the 2016 Democratic nominee, also appeared to diss Biden's chief rival, Bernie Sanders, by tossing a card with the Vermont senator's name on it over her head during a game called “Bag of Secrets.”

Host Jimmy Fallon asked Clinton what she thought of Biden's strong showing on Super Tuesday.

“I thought it was very exciting because, starting in South Carolina, he had so much energy and what he had to say was really enthusiastic and positive and about what he was going to do and who he was, and the people of South Carolina, obviously, rewarded that. And then, that kind of set off this momentum. And it carried him,” Clinton said.

Fallon then asked why people connect with Biden.

“I've known him for a really long time,” Clinton said. “I think people know he is a deeply decent person. He is a kind person. He doesn't take cheap shots at people. He doesn't insult people as a way of trying to put people down and lift himself up. He is such the opposite of what we currently have in the White House. I really think a lot of people had a chance to think about it as this contest got going, and decided, ‘Boy, the most important thing is that we retire the incumbent.' That's more important than anything else, and he has the experience. He knows what needs to be done. He can repair the damage that he would be inheriting, so I think that's what was going on in people's minds.”

During “Bag of Secrets,” Clinton drew cards with the names of current and former 2020 Democratic presidential candidates, before revealing secrets about them and allowing the audience to guess their identities. Clinton appeared to reveal “secrets” about Biden, Amy Klobuchar, Kamala Harris, and Pete Buttigieg, but threw one card onto the floor without commenting on it, prompting a dramatic reaction from Fallon.

Clinton, who defeated Sanders in a hotly contested primary in 2016, has said that “nobody likes” the self-described Democratic socialist. She has also called Sanders' campaign “just baloney.”