Tim Kraft, chairman of President Carter's reelection campaign, is tucked away in the coolest corner of a Democrat-packed bar here in the nation's first primary state and warming to his story.

"It's gotta be a technical knockout -- you can't take the championship away on points," he says, draining his beer glass and exhaling a stream of cigar smoke as he recounts his tale of pugilism and politics:

It was September 1976, and heavyweight boxing champ Muhammad Ali and President Ford were both fighting to retain their titles. Ali and Ken Norton "slugged it out toe-to-toe, no one ever hit the mat," and Ali won on a judges' decision.

After the fight, political strategist Bob Keefe turned to Kraft and acknowledged the lesson Norton learned that night: "It's tough to beat an incumbent."

And then the Carter camp went out and proved it could be done.

That lesson has not been lost on President Carter's challengers. They converted the traditionally sluggish fund-raiser for the Hampton County Democratic Committee Saturday night into the first head-to-head slugfest of the primary season.

Tom Quinn, who heads California Gov. Edmund (Jerry) Brown's "exploratory" presidential campaign, threw the opening blow, as he addressed the crowd and challenged the president to a series of debates in the Granite State.

"How do you respond to a staff suggestion from a undeclared candidate" asked Kraft later, adding, "The prospects of a debate are tenuous at best.

"Our preference would be the campaign in the kind of forum the president likes best -- town hall meetings. It's more fruitful for the president and the voters than an exchange between candidates."

The president's campaign will take a tack similar to the one employed in 1975 and 1976. Kraft said. "We're starting early, working hard, anticipating the toughest opponent and going all out to tell the president's story.

Brown-backer Quinn, who had joined Kraft at his table in the bar, moved in with a feint and a jab; "We know you're gonna win in New Hampshire but we're hoping to come within 10 points; after all, if you get anything less than 75 percent it's a loss for the president."

"I don't care what margin he sets up," said Kraft, playing the political ropes, "You can't outpoint the incumbent."

But if Sen. Edward M. Kennedy (D-Mass.) suddenly reverses his position and chooses to run, "it would be a titanic struggle," Kraft conceded.

"If Kennedy enters, I think we'd slug it out right down to the last damn delegate," he said.

In New Hampshire, the battle with Kennedy has already begun in earnest. State executive counselor Dudley W. Dudley, the second highest ranking Democrat here, has mounted a major write-in drive.

Nearly a quarter of the 150 Democrats here showed up sporting blue and white Kennedy campaign buttons to embrace Dudley's call to "march to the beat of a different drum. . .Ted Kennedy will hear us."

Sen. John Durkin, a frequent critic of the president who is threatening to run as a favorite son, said "the Democratic nomination is up for grabs."

"Carter is his own biggest political threat," Durkin said. "He won't be shut out, though; he may get the Ayatollah to vote for him after he sells the kerosene we need to Iran."

George Bruno, treasurer of the state committee and a 1976 Mondale campaign worker, agreed; "I can't see voting for Carter. . .Every time I pull up to a gas tank I think of Jimmy Carter and how we still don't have an energy policy."

But Carter was not without supporters. State Sen. Robert Preston said, "When Carter campaigned here last time he made an impact on the people; I really think the president has the upper hand and his support will be forthcoming."

And Victor Lessard, a local town selectman, said, "The way things are going now, I couldn't go for anyone but Carter." To Jerry Brown he says, "Never."

"No one tells us to buzz off," said Brown's New England coordinator Byron Georgious, who has just begun organizing here. "Our message is that Carter is going to lose and we believe Governor Brown is a very solid alternative who has the best chance of winning the general election."

Brown campaign officials said the governor will be in New Hampshire every month until the primary.

The next round in the primary fight here is set for Sept. 9 -- the annual Hillsborough County Democratic picnic, a traditional quadrennial forum for presidential politicking.

Campaign officials said Brown will personally face off against the president's mother, Miss Lillian, in next months bout.