In the first Democratic presidential debate, former Vice President Joe Biden and Sen. Kamala Harris, D-Calif., sparred over federally ordered busing, grabbing headlines and prompting speculation their fight will spill over into tonight's debate.

Biden had previously said at a July 24 fundraiser in Detroit that he was not going to be as "polite" in the coming debate, according to the Detroit News.

"This is the same person who asked me to come to California and nominate her in her convention," he added.

But if any hard feelings still lingered, it didn’t show when the two greeted each other at the beginning of the event.

“Go easy on me kid,” he said to her as they shook hands and she clasped his arm.

“How are you doing?" She said back. "Are you good?”

Biden replied, "I'm good."

Despite the candidates' outwardly calm appearances, the reaction online was less positive.

Ian Sams, Harris' press secretary, asked on Twitter, "Kid?"

Bloomberg reporter Jennifer Epstein noted Biden had his "Bidenisms" including "kid," but "urging a 54-year-old U.S. senator and opponent 'go easy on me, kid' is not a great start for his efforts to reset with this debate."

Christina Reynolds, the Emily's List VP of Communications, quipped, "She's a senator and a bad ass. Not a kid."

Contributing: Ledyard King