Bill Clinton has lost the campaign trail charisma he was once known for, especially in comparison to Sen. Bernie Sanders (I., Vt.), MSNBC host Chris Matthews said Monday.

"You know, I have to tell you, this is a hard call. I think Bernie Sanders right now is a better campaigner than Bill Clinton," Matthews said. "Bernie Sanders is on his game. Bill is a little rusty."

When he campaigned for president, Clinton was known for his crowd-winning charm. However, some have noted that he has lost his edge while stumping for his wife Hillary Clinton.

During Hillary's 2008 campaign, the former president got into trouble for making aggressive remarks against then-competitor Barack Obama. Bill Clinton dubbed Obama’s run for president a "fairy tale" and said that "a few years ago," Obama would’ve been "getting us coffee."

The former president has toned down his harsh remarks on the trail for Hillary’s 2016 run, though he slammed Sanders supporters over the weekend for their "vicious trolling" and "vicious" attacks.

"She and other people who have gone online to defend Hillary and explain–just explain–why they supported her have been subject to vicious trolling and attacks that are literally too profane often–not to mention sexist–to repeat," Clinton said.

Still, Clinton backed away from saying that Sanders has been "unfair" to Clinton in an interview with Andrea Mitchell Monday, dodging the question and praising open debate.

"Well, I think he's been inaccurate. Unfair is — the point is, we got a chance to debate him now. It’s all out in the open, that’s good," Clinton said.

In comparison, Sanders has an intense emotional connection with his crowds and is often referred to as the "heart" while Hillary Clinton is the "head." Clinton has struggled to match Sanders’s authenticity and popularity with young voters.