After President Donald Trump welcomed him to the 2020 presidential race last month by dubbing him “Sleepy Joe,” former Vice President Joe Biden responded with a moniker of his own at a fundraiser in South Carolina on Saturday.

“There’s so many nicknames I’m inclined to give this guy. You can just start with ‘clown,’” Biden said to laughter at the home of South Carolina Democratic Party Chairman Dick Harpootlian in Columbia, according to a pool report.

But even as he fired back at Trump, Biden said he wanted to run a campaign focused on the issues rather than on mudslinging.

“On every single issue and on every demeaning thing he says about other people, I have no problem responding directly. What I’m not going to do is get into what he wants me to do. He wants this to be a mud-wrestling match,” the former Delaware senator added.

He then expressed regret for once saying if he were in high school he would have taken Trump around back and “beat the hell out of him” for his comments about women.

“Well guess what, I probably shouldn’t have done that,” Biden said Saturday. “I don’t want to get it down to that level. The presidency is an office that requires some dignity.”

Biden, 76, entered the race last month as an instant front-runner. He has topped multiple polls of the crowded 2020 field and outraised all his rivals in the first 24 hours since announcing his presidential bid.

But in true Biden fashion, he stumbled last week by calling China “not competition” for the U.S. ― comments that invited criticism from both Republicans and Democrats alike. Rep. Tim Ryan (D-Ohio), who is also seeking the Democratic presidential nomination, called the remark “stunningly out of touch,” for example.

Biden alluded to the comments during his remarks at the South Carolina fundraiser on Saturday evening, pushing back on the notion that he was minimizing the Asian nation’s power.

“I don’t suggest China is not a problem,” Biden said, according to a pool report. “I’m the guy who’s been the toughest on ― I’ve spent more time with [Chinese President] Xi Jinping than anybody else, just because the nature of my job. He’s got problems, he’s got gigantic problems. Doesn’t mean he’s not a threat, doesn’t mean they’re not a threat.”

The longtime member and former chairman of the Senate Foreign Relations Committee touted his experience with world leaders. “I think, whether I’m right or not, I know as much about American foreign policy than anyone around, including even maybe [Henry] Kissinger,” Biden said.