Florida Governor Ron DeSantis ended his fading presidential campaign on Sunday and endorsed Donald Trump just two days before the pivotal New Hampshire primary, leaving former U.N. Ambassador Nikki Haley as Trump’s last long-shot challenger for the Republican nomination.

DeSantis’ decision, less than a week after his deflating loss to Trump in Iowa despite an enormous investment there, caps a stunning fall from grace after DeSantis had been widely seen as Republicans’ most promising alternative to Trump ahead of the general election in November.

His departure sets up the one-on-one battle that Haley has coveted against Trump, the former president who has maintained an iron grip on the Republican electorate despite facing four criminal prosecutions. Trump has pleaded not guilty in all the cases.

But DeSantis’ supporters appear more likely to switch allegiance to Trump than to the more moderate Haley. In New Hampshire, about two-thirds of DeSantis backers cite Trump as their second choice, said Andrew Smith, director of the University of New Hampshire Survey Center.

In a video posted on X, DeSantis endorsed Trump while delivering a parting shot at Haley.

“He has my endorsement because we can’t go back to the old Republican guard of yesteryear: a re-packaged form of warmed-over corporatism that Nikki Haley represents,” DeSantis said.

At a Sunday evening rally in Rochester, New Hampshire, Trump, who spent much of last year attacking DeSantis – praised the governor and said he was looking forward to working together to defeat President Joe Biden, the presumptive Democratic nominee.

Trump holds a double-digit lead over Haley in New Hampshire, according to polls, and his campaign hopes a second consecutive win will make his eventual nomination all but inevitable.

He also has a commanding lead in South Carolina, which votes on Feb. 24. A Haley loss in her home state where she served as governor from 2011 to 2017 would likely doom her campaign.

At a campaign event in Seabrook, New Hampshire, Haley drew cheers when she announced that DeSantis had dropped out.

“For now, I’ll leave you with this: May the best woman win,” she said.

David Kochel, a Republican strategist who has worked on five presidential campaigns, said DeSantis’ exit was unlikely to change the basic contours of the campaign, given that his support had cratered.