The race for governor intensified Monday as Dannel P. Malloy pitched himself to the Connecticut AFL-CIO as labor’s strongest ally and repeatedly jabbed at Ned Lamont, his chief rival for the Democratic nomination.

On Friday, Malloy smiled and shook Lamont’s hand at a televised debate. On Monday, no small talk passed between them, even though they sat side-by-side for two hours on stage in a ballroom at the Hartford Hilton. Malloy contrasted himself with Lamont–never using his opponent’s name–over taxing the rich and requiring private employers to offer paid sick days.

It was as though Malloy had decided over the weekend that spring training is over, and now the games count.

Malloy came with a hard sell for an influential audience that flatly rejected him four years ago, when New Haven Mayor John DeStefano won labor’s endorsement and the Democratic nomination.

“There are two statewide unions in the AFL-CIO who have endorsed so far, the Communication Workers and Operating Engineers. And I have both of them,” Malloy said. “So we’re off to a better start.”

Unable to compete with the resources of the wealthy Lamont, who spent $17 million of his own money on a Senate campaign in 2006, Malloy badly needs labor as an equalizer.

He pounced after Lamont did not directly answer a question about whether he would support raising income taxes on residents who earn more than $250,000 annually.

“I have always favored a progressive income tax, and I don’t refuse to answer the question,” the former Stamford mayor told his audience. “If you are unwilling to answer that benchmark question, have you earned the support of labor?”

Lamont said, “I can’t out promise everybody here at this table, but I promise you that I will be there fighting for your jobs every day.”

He shrugged off Malloy’s digs.

“I suppose that he took a few jabs,” Lamont said after the forum. “I’m sticking to my message, why I’m running for governor, what I want to do. I’m not talking about anybody else. I don’t think that helps Democrats. I don’t think it helps the dialogue.”

Lamont said his answer about raising the income tax has not changed: he is not ruling out new taxes.

“I said the same thing I’ve said for the last six months: First and foremost, you have to convince skeptical taxpayers that their money is being well spent,” Lamont said.

One reason for Malloy’s new aggressiveness is that his campaign expects Lamont to begin airing television commercials in the next month, something no other Democrat can afford.

Lamont has opted out of the state’s voluntary public financing program for campaigns, saying the legal status of the program is uncertain and that the wealthy Republican frontrunner, Tom Foley, already is on the air

Malloy has said Lamont’s decision undermines campaign finance reform.

His focus is on winning labor support. Four years ago, Malloy could not block an AFL-CIO endorsement of DeStefano.

An endorsement requires a two-thirds vote by delegates to federation’s summer convention, and candidates in statewide Democratic primaries typically fail to cross that threshold.

The federation endorsed no one in two previous Democratic gubernatorial primaries in 1990 and 1994, said John Olsen, the president of the AFL-CIO.

This year, the AFL-CIO convention will not be held until a week after the Aug. 10 primary. The best Malloy can hope for prior to the primary is a recommended endorsement by the federation’s Committee on Political Education, as well as endorsements by individual unions that belong to the AFL-CIO.

A Quinnipiac University poll last week showed Lamont leading Malloy, 28 percent to 18 percent, with no other Democrat topping 3 percent. But 44 percent of Democrats remain undecided.

On Monday, Lamont and Malloy shared a stage with three other Democrats — First Selectwoman Mary Glassman of Simsbury, former state Rep. Juan Figueroa and First Selectman Rudy Marconi of Ridgefield — and one Republican, Mayor Mark Boughton of Danbury.

Figueroa, who is on leave as president of the Universal Health Care Foundation of Connecticut, matched Malloy’s fervor on taxes and mandating paid sick days.

“I would tax the rich,” Figueroa said.

Marconi, who is pushing gateway tolls to be installed on the interstate highways at the state border as a major new source of revenue, also said he would support raising the income-tax on higher earners.

All the Democrats and Boughton supported the prevailing wage law for public construction projects.

All five Democrats supported raising the minimum wage.

Boughton did not. Nor would he agree to a tax increase.

He told the union delegates that the public will not support any tax increase, because state government has no credibility after running up billions in long-term debt and failing to address a fiscal crisis that is expected to produce a $3.8 billion debt next year.

“Folks, there really is no easy way or simple way to solve Connecticut’s problems,” Boughton said. “We’re broke and we’re broken. We’re broken because our political process has ground to a halt.”

Lamont complimented Boughton for showing up, urging the delegates to applaud the sole Republican.

“He is the Republican who had the courage to come here,” Lamont said. Of the others, he said, “I can’t believe they didn’t show up.”

Malloy had no such kind words. He sharply contradicted Boughton – and Lamont by inference.

“We are not broke, and we are not broken. We’re going to rebuild this state, and it’s going to be led by labor and contributions that labor makes,” he said.

After the forum, Malloy said it was appropriate to draw distinctions with his competitors, though he still did not refer to Lamont by name.

“There are distinctions,” he said. “The reality is I support campaign finance reform. Another candidate doesn’t. I support paid sick days. Another candidate doesn’t.”

Malloy did not exit the Hilton with the other candidates. He followed the union delegates down one floor to a room set up for their private lunch. He worked the room by himself, stopping by every table.