Millionaire businessman Ned Lamont opened a double-digit lead over veteran Sen. Joe Lieberman less than a week before Connecticut's Democratic primary, according to a poll released Thursday.

Lamont, a political novice, had support from 54 percent of likely Democratic voters in the Quinnipiac University poll, while Lieberman, now in his third term, had support from 41 percent of voters. The sampling error margin was plus or minus 3 percentage points.

A similar survey July 20 showed Lamont with a slight advantage for the first time in the campaign.

"Senator Lieberman's campaign bus seems to be stuck in reverse," poll director Douglas Schwartz said. "Despite visits from former President Bill Clinton and other big-name Democrats, Lieberman has not been able to stem the tide to Lamont."

Lieberman, 64, one of the Senate's most well-known Democrats and his party's nominee for vice president in 2000, has been harshly criticized in Connecticut for his support of the Iraq war and his perceived closeness with President Bush.

Lamont, 52, who owns a successful cable television firm, has been able to tap into rank-and-file Democratic voters' frustration with Lieberman as well as his personal wealth, contributing $3 million to his campaign.

"Although we realize the only vote that counts is Aug. 8, we hope this energizes our base," said Liz Dupont-Diehl, a spokeswoman for the Lamont campaign.

The Lieberman campaign said the poll shows that much work must be done by to win Tuesday's primary.

"We are working night and day to make sure Sen. Lieberman wins the primary. We are going to fight for every last vote," campaign spokeswoman Marion Steinfels said.

Lieberman has been collecting signatures to petition his way onto the ballot as an independent candidate should he lose Tuesday's primary. Unaffiliated voters outnumber Democrats and Republicans in the state, and Lieberman has typically drawn strong support from both unaffiliated and Republican voters.

The poll did not examine how Lieberman and Lamont would fare if Lieberman ran as an independent in the general election.

Lieberman recently called on President Clinton to visit the state on his behalf, and Clinton's endorsement has been used in the campaign's televised ads. But that apparently had little effect on voters; of those who supported Lieberman, 78 percent said Clinton was not a reason for their support.

The telephone survey of 890 likely Democratic primary voters was conducted from July 25 to 31.