"Chris MurphyChristopher (Chris) Scott MurphyBiden huddles with group of senators on Ukraine-Russia tensions Overnight Defense & National Security — Texas hostage situation rattles nation Senators to meet with Ukraine president to reaffirm US support MORE is not happy that his lack of a work ethic has been exposed, but that’s the least of his worries," says an email from campaign manager Corry Bliss that goes along with the ad.

"Summarize" comes just a day after the release of a poll that showed McMahon leading Murphy by three percentage points. But a new poll flips that lead, with Murphy ahead of McMahon by four percentage points.

According to the poll from left-leaning Public Policy Polling, Murphy has 48 percent support to McMahon's 44 percent support. McMahon's favorability numbers are split pretty evenly in the poll, with slightly more -- 47 percent -- of voters rating her unfavorably than the 45 percent who have a favorable opinion of her, and only eight percent of voters are unsure about the candidate.

Murphy faces a similar gap in his favorability numbers, with 41 percent of voters viewing him unfavorably and 39 percent viewing him favorably -- but a full 20 percent of voters are still unsure about him.

The new poll also indicates Connecticut voters mostly have their minds made up, with only 8 percent of respondents saying they're still undecided in the race.

It was conducted among 881 voters from Aug. 22-23.