Republican businessman Mike McFadden has a clear shot a Democratic U.S. Sen. Al Franken, after GOP delegates dashed expectations and selected him for the November fight.

After flirting with an outsider candidate in St. Louis County Commissioner Chris Dahlberg, Republicans embraced McFadden's promise of superior fundraising and organization. The battle between the two went into the pre-dawn hours Saturday and, after a break for sleep, continued until McFadden clinched delegates' endorsement Saturday afternoon.

"I'm so honored to be your endorsed candidate for the United States Senate. Thank you from the bottom of my heart, I humbly accept," McFadden said, his voice flagging and his energy renewed. "I look forward to taking the fight to Al Franken."

McFadden, who has raised nearly $3 million for the coming battle and promised more to come, was thought to be a long-shot to win party backing. Unlike Republicans who had won endorsement in years past, he has had little involvement in party politics and refused to drop out if delegates chose someone else.

McFadden convinced activists, sick of losing Minnesota races, that he could win in November.

"I am the candidate, undoubtedly, without an exception, to beat Al Franken," McFadden said.

He said last year he was inspired to run after seeing the frustrating results of 2012 election results. McFadden left his job as an executive at Lazard Middle Market to vie against Franken. A father of six who often has at least one off-spring with him at events, he felt he had something to offer.

"I've never done this before so I didn't know what to expect," he said a month into his campaign.

Many of the power players in Washington -- including former Sen. Norm Coleman, who lost his seat to Franken six years ago -- rallied around him. On Saturday morning, retiring U.S. Rep. Michele Bachmann let convention delegates know that she, too, was supporting McFadden.

He has also had stumbles. Appearing before the press and fellow Republicans, he avoided disclosing some specifics of his beliefs. Dahlberg this spring accused him of disrespecting Minnesotans by refusing to tell them what he thinks.

In early speeches, he appeared ill at ease with the crowd.

But at the convention, he was more comfortable and had a surge that surprised delegates and even some on his campaign team.

"We're flying by the seat of our pants," said volunteer Harry Niska, as delegates prepared to cast their ninth-ballot in what proved to be an 10-ballot contest. "But at least we're flying."

McFadden campaign manager Brad Herold said his team had quietly worked for months to make the endorsement happen. They had a strategy team studying the delegates, for both the Senate race and the governor's race. They hired staffers from both inside and outside Minnesota and a detailed data plan for the convention.

"We made over 50,000 phone to a universe that's only about 6,600 delegates," Herold said. He said he was not shocked by the result, but admitted some of the delegates may have been.

"If you have good organization, you don't talk about it. I look forward to telling Al Franken about our superior organization in November," Herold said.

McFadden forced the convention into a three-way tie in early going, with he, state Sen. Julianne Ortman and St. Louis County Commissioner Chris Dahlberg splitting the vote. After Ortman dropped out, Dahlberg leapt ahead.

Dahlberg presented himself as someone who could stand true on issues and could win over Democratic voters. Unlike McFadden, he pledged to drop out if delegates do not select him.

"Let's get it done!" Dahlberg told delegates. "I will abide by the endorsement. No gray issues."

But he could not get it done. After more than 12 hours of voting, delegates overwhelmingly moved to back McFadden for the coming fight.

The support was not unanimous.

Several tea party activists said McFadden will have a hard time winning the conservative core of the party.

"A guy like him will not attract a lot of people in this movement," Jake Duesenberg, a tea party organizer. He said some may stay home in November if the party keeps, "giving us candidates we don't believe in."

Updated