In a two-way match-up, Hillary Clinton would lead Donald Trump by 9 points, 47 percent to 38 percent. | AP Photo Post-debate poll: Clinton leads by 7 points in New Hampshire

Hillary Clinton leads Donald Trump by 7 points in New Hampshire, according to a new poll conducted entirely after the first presidential debate this week.

The poll, conducted by MassINC Polling Group for WBUR-FM in Boston, shows Clinton leading Trump, 42 percent to 35 percent. Libertarian Gary Johnson earns a large share of the vote, 13 percent, with Green Party nominee Jill Stein at 4 percent and a combined 6 percent undecided or preferring another candidate.

Johnson and Stein are cutting into Clinton’s lead slightly, the poll shows. In a two-way match-up, Clinton would lead Trump by 9 points, 47 percent to 38 percent.

Independents make up a large percentage of the New Hampshire electorate: As of last month, 39 percent of the state’s voters were registered as undeclared. In 2012, 43 percent of general-election voters identified as independents on the exit poll — far higher than the 29 percent of voters nationwide who said they were independents.

Likely voters, on balance, have negative views of all four candidates, according to the poll. Clinton has the highest favorable rating, 40 percent — but 51 percent have an unfavorable opinion of the Democratic nominee. Trump’s image rating is significantly worse: 32 percent favorable, to 61 percent unfavorable. And even Johnson (22 percent favorable/28 percent unfavorable) and Stein (14 percent favorable/23 percent unfavorable) are viewed more negatively than they are positively.

Four-out-of-five likely voters surveyed said they watched Monday night’s debate, and 59 percent of debate-watchers said Clinton did the best job. Only 19 percent said Trump won.

Twenty-seven percent of debate-watching likely voters said it made them more likely to support Clinton, while 17 percent said it made them less likely. Trump did himself more harm: Only 13 percent said the debate made them more likely to back Trump, compared to 30 percent who said it made them less likely to vote for him. But majorities said it made no difference how they view either candidate.

New Hampshire is the smallest battleground state — awarding only 4 electoral votes — but both campaigns are actively contesting it. Clinton and Sen. Bernie Sanders (I-Vt.) campaign there together on Wednesday, and Trump followed with a visit on Thursday.

Clinton’s 7-point advantage in the poll matches her 7-point lead over Trump in POLITICO’s Battleground States polling average. The survey is one of the first public, live-caller poll — either national or state-level — conducted entirely after the debate. A Detroit News/WDIV-TV poll in Michigan released Thursday night gave Clinton an identical, 42-percent-to-35-percent lead over Trump.

The MassINC Polling Group/WBUR-FM poll was conducted September 27-29, surveying 502 likely voters. The margin of sampling error is plus or minus 4.4 percentage points.