With his exit from the GOP race for president on Sunday, Ron DeSantis made clear that he doesn't just want Donald Trump to win — he wants Nikki Haley to lose.

Why it matters: DeSantis dropping out just before Tuesday's New Hampshire primary — and immediately endorsing Trump — likely hurts Haley hours before a contest where the former UN ambassador needs to win or finish a strong second.

• By pulling the plug on his campaign, the Florida governor struck the latest blow in his increasingly bitter fight with Haley.
• For months, DeSantis privately told donors Haley had no chance in a 1-on-1 race against Trump. His campaign seethed as many of them gave to Haley anyway.
• Now, DeSantis believes he'll be proven right.

Driving the news: In a video announcing his exit, DeSantis said he endorsed the former president "because we can't go back to the old Republican guard of yesteryear — a repackaged form of warmed-over corporatism that Nikki Haley represents."

• Haley has been polling within striking distance of Trump in New Hampshire. But polls show that most DeSantis voters prefer Trump to her.
• DeSantis' exit — and endorsement of Trump — could help deliver a devastating blow to Haley's overall prospects for the GOP nomination. But in New Hampshire, DeSantis has been polling far behind Trump and Haley. So the effect of his departure is less clear there.

Zoom in: The relationship between DeSantis and Haley became more and more tense as they battled to be the Republican alternative to Trump.

• At a CNN debate in Iowa on Jan. 10, they accused each other of lying and hurled insults such as "mealy-mouthed" and "so desperate."
• A senior DeSantis aide told Axios that Haley was and is "irrelevant."

Last fall, DeSantis and his team tried to stop large donors from backing Haley, arguing she was going to spend most of the money attacking DeSantis — whose support would go to Trump, according to a person familiar with the conversations.

• Part of that prediction has come true: Haley's main Super PAC spent more than $23 million on ads hitting DeSantis in Iowa and not Trump, per AdImpact.
• Even so, DeSantis edged out Haley for second place in the Iowa caucuses. Both finished well behind Trump.

Between the lines: DeSantis' team was surprised that Haley announced a $4 million ad buy in South Carolina next week — believing that if Haley had spent that money in Iowa, she could have edged out DeSantis for second place, according to a source familiar with DeSantis' operation.

Zoom out: Haley's team has long rejected DeSantis' criticisms and argued that she could win a 1-on-1 race with Trump.

• Haley told CNN on Sunday that she is "absolutely" going to stay in the race through South Carolina's primary on Feb. 24. As part of a "First-in-the-South Swing," her campaign announced a rally in Charleston, S.C., for Wednesday night, 24 hours after New Hampshire polls close.
• New Hampshire — which allows independents to participate in the primary and includes healthy percentages of moderate and college-educated voters — is an ideal state for Haley to give Trump her best shot.

What they're saying: "Ron DeSantis has been a good governor, and I wish him well," Haley said in a statement. "So far, only one state has voted. Half of its votes went to Donald Trump, and half did not. We're not a country of coronations."

• Trump said he would "retire" his "Ron DeSanctimonious" nickname for DeSantis and complimented the Florida governor on his run.