CONCORD, N.H. — New Hampshire Rep. Chris Pappas won the state's open U.S. Senate seat Tuesday, defeating Republican former Sen. John E. Sununu, according to The Associated Press, which called the race shortly before 8:30 p.m. with about 20% of the vote counted, WCAX reported. Sununu has conceded, according to WCAX.

Pappas, a Democrat, will succeed retiring Sen. Jeanne Shaheen, who has held the seat for 18 years. Shaheen first won it in 2008 by defeating Sununu, who was seeking a second term at the time, NBC News reported.

Pappas becomes the first openly gay man elected to the U.S. Senate, according to the AP.

Pappas, 46, has represented New Hampshire in the U.S. House since 2019 and is a member of the bipartisan Problem Solvers Caucus, CBS News reported. Before Congress, he served on the New Hampshire Executive Council from 2013 to 2019 and in the state House from 2002 to 2006, according to the New Hampshire Bulletin. He has also helped run his family's restaurant in Manchester, according to the AP.

Pappas cast the race as a referendum on the president. "This election is about Team New Hampshire versus Team Trump," he said during the campaign, the AP reported.

President Trump endorsed Sununu early in the Republican primary, but Sununu worked during the race to distance himself from the president, according to WCAX. Late in the campaign, Sununu released an ad saying he had never met Trump and promising to oppose the president's policies when they were bad for New Hampshire, CBS News reported.

Sununu, a former congressman who served one term in the Senate, comes from one of the state's best-known Republican families. His father and his brother both served as governor, NBC News reported.

Republicans had seen the open seat as one of their few chances to pick up a Senate seat this year, according to CBS News. New Hampshire has not elected a Republican to the Senate since 2010.

Pappas won the Democratic nomination in September, defeating Karishma Manzur, according to NBC News.

His departure from the House leaves the 1st Congressional District seat open. Democrat Stefany Shaheen, the senator's daughter, faced Republican Anthony DiLorenzo for it on Tuesday, CBS Boston reported.