Tea Party favorite Ben Sasse won the Republican nomination for an open Senate seat in Nebraska Tuesday night, after a heated and costly primary battle that drew heavy national attention.

Sasse, a university president, was able to hold off former state treasurer Shane Osborn and dark horse candidate Sid Dinsdale, who had begun to surge in recent weeks. Sasse grabbed 48 percent of the vote with Dinsdale finishing second and Osborn finishing third, according to preliminary returns.

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"We were never doing this because we need another job," Sasse told supporters Tuesday night. "We were only going to do this if we were going to talk about big bold conservative ideas."

The win makes Sasse a huge favorite in November's general election, where he'll face Democrat Dave Domina, an Omaha attorney. The winner will replace Republican Mike Johanns, who didn't seek a second term.

Sasse, the president of Midland University, had steadily gained the backing of some of the most influential conservative groups and figures. His victory is a huge win for the Tea Party, as the movement has struggled to gain traction this year in the primaries.

Osborn had the backing of allies of Senate Minority Leader Mitch McConnell, R-Ky., and ran an aggressive campaign. Further scrambling the race, Pinnacle Bank President Dinsdale had sought to capitalize on the Sasse-Osborn fight and had climbed in the polls.

In recent weeks, big names gravitated to Sasse's side, including Sarah Palin and Texas Republican Sen. Ted Cruz. Sasse also has the backing of the Club for Growth, the Tea Party Patriots, the Senate Conservatives Fund and FreedomWorks.

"Ben Sasse won this race because he never stopped fighting for conservative principles," said Matt Hoskins, executive director of the Senate Conservatives Fund, which spent more than $1.2 million to help Sasse.

Cruz said Sasse's win "is a clear indication that the grassroots are rising up to make D.C. listen."

Sasse focused on his conservative credentials, opposition to abortion, support for gun rights and goal of repealing and replacing the health care law.

In one 30-second ad, Sasse's two young daughters, Alex and Corrie, talked about how much their dad opposed the Affordable Care Act. "He wants to destroy it," said one daughter. "He despises it," said the other.

However, Sasse advised former Health and Human Services Secretary Mike Leavitt's firm as the group reached out to businesses and organizations in 2010 to explain and implement the new law. Osborn recently began running a 30-second TV ad linking Sasse to writings and speeches from several years earlier commenting on elements that would become part of the law firmly opposed by most Republicans.

Outside groups and the candidates have spent millions on the race in which the GOP winner is widely expected to prevail in November. The National Republican Senatorial Committee, the party's campaign operation, remained neutral.

The Tea Party movement has struggled in earlier contests, with their favored candidates losing to establishment favorites in Texas, North Carolina and Ohio.

Looking ahead to upcoming primaries, the Tea Party's chances to upset incumbents have been diminishing in Kentucky, Kansas, Idaho and Mississippi.

In Nebraska's GOP primary for governor, Omaha businessman Pete Ricketts narrowly defeated Attorney General Jon Bruning. Term limits prevented Republican Gov. Dave Heineman from running again.

The Associated Press contributed to this report.