Ted Cruz holds off Trump to win Iowa Republican caucus
Sen. Ted Cruz of Texas speaking at the 2015 Conservative Political Action Conference (Gage Skidmore/Flickr)

Sen. Ted Cruz (R-TX) won an upset victory Monday in the Iowa Republican caucus, making frontrunner Donald Trump a loser in his first-ever election, ABC News reported.

Polls released over the weekend showed Trump with a five-point lead over Cruz, but few likely Iowa voters listed the real estate tycoon and reality TV star as their second choice. On Monday, the Texas Tea Party lawmaker captured the support of 28 percent of caucus participants, compared to Trump's 24 percent.

Trump is polling well ahead of Cruz and other GOP challengers in New Hampshire, but his Iowa loss raises new concerns about his ability to translate months of poll support into votes in his first political campaign.

Cruz's win also suggests that he was right to attack Trump after months of laying off the frontrunner.