Pete Buttigieg has moved slightly ahead of Senator Bernie Sanders in New Hampshire, besting the Vermont independent by 1cq percentage point among likely Democratic presidential primary voters. Alyssa Schukar/The New York Times

Former South Bend, Ind., mayor Pete Buttigieg has moved slightly ahead of Senator Bernie Sanders in New Hampshire, besting the Vermont independent by 1 percentage point among likely Democratic presidential primary voters in a Boston Globe/WBZ-TV/Suffolk University poll released Friday night.

Buttigieg, who squeaked past Sanders in the troubled Iowa caucuses, increased his support in New Hampshire to 25 percent, compared to 24 percent for Sanders, in Friday’s poll, which has a margin of error of plus or minus 4.4 percentage points.

Senator Elizabeth Warren saw a small increase to 14 percent on Friday, keeping her in third place, while former vice president Joe Biden, whose numbers have slipped all week after he fell short of expectations in the Iowa caucuses, held steady at 11 percent for a second day.

Sanders won the New Hampshire primary in 2016.

This latest poll, the fifth of seven that the Suffolk University Political Research Center is conducting in the run-up to the nation’s first primary on Tuesday, was concluded Friday night while seven candidates participated in perhaps the race’s most crucial debate, one that could further shake up the rankings.

About a third of pollers’ calling was conducted after the debate began, but it is too early to see its effects in the results, according to David Paleologos, director of Suffolk’s Political Research Center.

“We’ll have a better picture on Saturday,” when the sixth poll in the series is released, Paleologos said.

Buttigieg, who laid into Sanders in Friday’s debate, accusing him of “my way or the highway” politics, started the week off with 11 percent support, putting him 13 percentage points behind the Vermont senator in Monday’s poll. Buttigieg edged ahead in the latest survey, after a dramatic jump of 14 percentage points.

Sanders, who criticized Buttigieg on Friday as being beholden to billionaire donors, remained virtually locked in polling all week, thanks to his unwavering core of diehard supporters.

“Sanders hasn’t faltered at all. His support’s been rock solid, but he’s been around that 24, 25 percent all week,” Paleologos said. “He’s very strong among young voters, and really the core of his success depends on younger voters.”

If enough millennial and Gen-Z voters turn out at the polls on Tuesday, Paleologos explained, Sanders is likely to win. But if they don’t, he could fall to Buttigieg, who is stronger among older voters.

Biden, who dropped from 18 percent in Monday’s New Hampshire poll to 15 percent Tuesday, then 12 percent, and 11 percent on Thursday, held steady Friday despite taking two days off from campaigning in New Hampshire to prepare for the debate.

Warren held steady at 14 percent Friday, after coming in at 13 percent on Monday and Thursday, with dips to 10 percent Tuesday and 11 percent Wednesday.

Senator Amy Klobuchar of Minnesota, billionaire environmentalist Tom Steyer, and tech entrepreneur Andrew Yang, who were all on Friday’s debate stage, scored in the single digits, as did the race’s other remaining Democrats, and 7 percent of voters were undecided.