Republican Donald Trump's surprise defeat in Iowa at the hands of U.S. Senator Ted Cruz reflected shortcomings in his get-out-the-vote operations and an over reliance on his celebrity status in a state where voters prefer the personal touch.

The New York billionaire and former TV reality star generated much enthusiasm for his anti-establishment message, but in the end he was outmuscled by Cruz' more traditional ground game and saw some late-deciding voters side with U.S. Senator Marco Rubio.

All signs had pointed to a Trump victory in the first nominating contest in the race for the White House, with the Des Moines Register's influential poll giving Trump the lead on the weekend before Iowans went to caucus on Monday.

The loss, while not by a large margin, raised questions about Trump's ability to perform as well in voting contests as he does in polls. Prior to Monday, Trump had repeatedly boasted that he would easily win Iowa, and he has been the front runner in most national polls since last summer.

Sensing victory, Trump had mocked Cruz's ground game in the hours before voters went to their caucus sites.

“I hear they all have these great ground games, they've got people pouring in on buses and trucks,” Trump said at a campaign rally. “They are spending all the money they have from special interests. For our country, I want the person who is going to spend the least amount and get the best results."

Trump had relied on what Iowa Republican Party Chairman Jeff Kaufmann told Reuters was a "stealth" ground effort. For some though, the specifics of Trump's plan for turning out his supporters on Monday were questionable.

Instead of aggressively trying to convert any and all Republicans to his cause as Cruz did, Trump relied mostly on signing up supporters from among those who attended his rallies.

The challenge Trump faced was trying to persuade these people, many of whom had never participated in a caucus before, to show up.

Tana Goertz, Trump's Iowa campaign chair, was frequently an introductory speaker at Trump events and would encourage attendees to make sure they knew where to go to caucus. Leaflets were passed out reassuring voters that the ballot is secret and, "most caucuses take less than 1 hour."

"It's new to a lot of these people who were supporting him," said David McNeer, of Newton, Iowa, who steered his precinct into overwhelmingly voting for Trump. "It may be at the end that some of them didn't come out like they thought were going to come out."

Cheeseburgers not caviar

Trump's bombastic style and flair for the dramatic may in the end have not helped as much as he would have hoped.

As Cruz and Rubio went the more traditional route of talking to small groups of people at pizza parlors and hotel conference rooms, Trump would make a dramatic entrance in his private jet, emblazoned with his name, and tear into his rivals at rallies attended by thousands.

He made pandering comments like wanting to buy a farm in Iowa and hoping his pregnant daughter would deliver her baby in the state. He did few small events.

Gary Updegraff, an enthusiastic Trump backer and precinct chairman in Des Moines, said he believed Trump would adjust his style.

"He's a very smart man, he’s going to analyze this with his people, he’ll talk to his family probably about it. I think the genuineness of Donald Trump needs to come out a little bit more," Updegraff said.

Trump took some initial steps in this direction in the final days before the caucus. He appeared with evangelical leader Jerry Falwell Jr., who asked Trump friendly questions that played up the candidate's contributions to charitable causes and pointed out he served cheeseburgers, not caviar, on his plane.

At least some of his supporters think Trump might have performed better if he had participated in a Fox News debate last week instead of boycotting in opposition to anchor Megyn Kelly and a Fox news release he felt had a biting tone.

"I think a lot of things caught up to him here in the last couple of weeks," said Trump supporter Brett Ridge of Des Moines, speaking shortly after Trump's concession speech. "When it comes down to it, he should have been at the debate last week."

Trump noted in his concession speech that some had argued he would never do well in the state.

"Iowa, we love you," Trump said in defeat. "You are very special. I think we might come back here and buy a farm."

(Reporting by Steve Holland; Additional reporting by Ginger Gibson, editing by Paul Thomasch and Ross Colvin)