"You can call me Hillrod," said Clinton of her WWE persona, and Obama asked the audience, "Do you smell what Barack is cooking?"
While Clinton held a late-night rally in Philadelphia, Obama laughed through his appearance on Jon Stewart's "The Daily Show."
But there was a different tone this morning, as both candidates appeared on "Good Morning America" to discuss a nuclear Iran and their expectations for the outcome of today's primary vote.
In an interview with ABC News' Chris Cuomo, Clinton expressed her toughest stance yet on Iran's nuclear ambitions and the potential threat the country poses to American allies.
"If Iran were to launch a nuclear attack on Israel what would our response be?" Clinton said. "I want the Iranians to know that if I'm the president, we will attack Iran. That's what we will do. There is no safe haven."
"Whatever stage of development they might be in their nuclear weapons program in the next 10 years during which they may foolishly consider launching an attack on Israel, we would be able to totally obliterate them," Clinton said.
Clinton's tough talk on Iran came a day after she launched a TV ad in Pennsylvania that included the ominous face of al Qaeda leader Osama bin Laden. Clinton introduced bin Laden into the campaign along with the narrator's voice warning, "It's the toughest job in the world. You need to be ready for anything."
When asked how he would respond to a nuclear attack by Iran, Obama told ABC News' Robin Roberts that he would do everything he could to prevent the country from having weapons in the first place.
"I was absolutely clear about the fact that if Iran used nuclear weapons on Israel, or any of our allies, we would respond forcefully and swiftly," said Obama.
"But, in some ways, this hypothetical presupposes a failure to begin with," said Obama. "We shouldn't allow Iran to have nuclear weapons, period."
"I have consistently said that I will do everything in my power to prevent them from having it and I have not ruled out military force as an option," he said.
Obama suggested that Clinton's use of terms such as "obliterate" in reference to Iran are ineffective "saber rattling."
"Talk using words like obliterate doesn't actually produce good results," said Obama. "I think the Iranians can be confident that I will respond forcefully, and it will be completely unacceptable if they attacked Israel, or any other of our allies in the region, with conventional weapons or nuclear weapons."
When asked what the measure is by which she needs to win the Pennsylvania primary, Clinton said, "Well, I have to win. I believe that's my task."
"I know very well that I'm in a real fight here," Clinton said about her tight race against Obama. "Every time I turn around there are posters at bus stops and train trips and he's got an enormous cash advantage."
Clinton told Cuomo that Pennsylvania is a must-win state for any Democrat who wants to win the White House in November.