MANCHESTER, N.H. - Former President Donald Trump easily won New Hampshire’s primary on Tuesday, seizing command of the race for the Republican nomination and making a November rematch against President Biden feel all the more inevitable.

The result was a setback for former U.N. Ambassador Nikki Haley, who finished second despite investing significant time and financial resources in a state famous for its independent streak. She’s the last major Trump challenger after Florida Gov. Ron DeSantis ended his presidential bid over the weekend, allowing her to campaign as the sole alternative to Mr. Trump.

With more than 95% of the expected vote reported, there’s a single delegate left to be allocated in the New Hampshire Republican primary. But no matter where that spare ends up as the final ballots are counted, Mr. Trump is far ahead in the overall delegate count through the first two contests.

New Hampshire assigns its Republican delegates proportionally among candidates who win at least 10% of the vote statewide.

Mr. Trump, who placed first, and Ms. Haley, who placed second, will split the state’s 22 delegates, as no other candidate hit 10%. Mr. Trump will receive 12 delegates, more than half of the state’s total. Ms. Haley has locked down nine delegates, but she’s on the cusp of receiving 10.

If Ms. Haley does end up with 10 delegates, that’s the end of the count for New Hampshire. If she doesn’t reach 10, however, then we’re left with one extra delegate. According to RNC rules in New Hampshire, that extra delegate goes to the person who won the most votes: Mr. Trump.

In Iowa, Mr. Trump won 20 delegates to Ms. Haley’s eight.

Mr. Trump’s allies ramped up pressure on Haley to leave the race before the polls had closed, but Ms. Haley vowed after the results were announced to continue her campaign. Speaking to supporters, she intensified her criticism of the former president, questioning his mental acuity and pitching herself as a unifying candidate who would usher in generational change.

“This race is far from over. There are dozens of states left to go,” Ms. Haley said, while some in the crowd cried, “It’s not over!”

Mr. Trump, meanwhile, can now boast of being the first Republican presidential candidate to win open races in Iowa and New Hampshire since both states began leading the election calendar in 1976, a striking sign of how rapidly Republicans have rallied around him to make him their nominee for the third consecutive time.

At his victory party Tuesday night, Mr. Trump repeatedly insulted Ms. Haley and gave a far angrier speech than after his Iowa victory, when his message was one of Republican unity.