Hillary Clinton was given the fright of her life as veteran socialist senator Bernie Sanders pushed her to the limit in the Iowa caucuses, on a night of extreme drama in the first test of the US presidential election year.Ted Cruz, the maverick Texas senator, used his formidable ground game to beat the bombastic property tycoon Donald Trump into second place in the Republican race, reports theguardian.And with Florida senator Marco Rubio enjoying a strong night in third place, the congested Republican field could yet be reshaped as a head-to-head between two Cuban Americans vying to become the first Latino president of the United States.Yet it was in the Democratic race where the closest of finishes caused high anxiety in the Clinton camp.With more than 99% of the precinct results in, Clinton led 49.9% to 49.5% over Sanders after seeing an apparently comfortable lead slip. The Associated Press and multiple outlets said the race was simply too close to call, though the Clinton camp claimed a narrow victory.Both candidates will now move on to New Hampshire buoyed up, Clinton with a “sigh of relief” that her bid to be the first female president of the United States is alive, and Sanders believing that his revolution against the “billionaire classes” truly began in the snowy cornfields of Iowa.With half of the results in across the rural midwest state, Clinton appeared to be easing to victory, three points up on the Vermont senator, whose relatively ramshackle campaign seemed to be no match for her mighty political machine.But as the night wore on, Clinton’s lead shrank to two and then one point, until she was locked in a virtual tie with the 74-year-old whose passion has ignited a fervour among young Americans.Appearing onstage in Des Moines before the final tally arrived, Clinton hailed “a contest of ideas” and appeared battle-ready for the fight of her political life.She congratulated her opponent, saying: “I am excited about really getting into the debate with Senator Sanders about the best way forward to fight for us in America.”The democratic socialist, though, had stolen some momentum heading into the New Hampshire primary on 9 February – and a prolonged fight appears inevitable, a far cry from what had been envisaged as a graceful procession toward the nomination for Clinton.By almost 11pm local time, the two Democratic rivals had both given what sounded like competing victory speeches.Sanders raised the roof as he told supporters: “While the results are still not known, it looks like we are in virtual tie,” adding: “The people of Iowa have sent a very profound message to the political establishment, the economic establishment, and by the way to the media establishment.”Largely written off by both the media and Democratic leaders, Sanders has been attracting huge crowds across the state since he first started campaigning here in the summer and made Clinton’s poll leads that reached as high as 32% all but evaporate.Late on Monday night in Des Moines, a crowd at Sanders’ victory party was watching him inch to within 0.2 percentage points down, to a tie on the television overhead, then back down to 0.2 points. Someone put on Sanders’ fight song – the Simon & Garfunkel anthem America. “They’ve all come to look for America,” sang the throng.Speaking to reporters on a chartered plane flying to New Hampshire, Sanders called on officials to take the unusual step of revealing underlying voter totals.Delegates are awarded in the Iowa Democratic contest on a precint-by-precinct basis, irrespective of the state-wide vote for each candidate.“I honestly don’t know what happened. I know there are some precincts that have still not reported. I can only hope and expect that the count will be honest,” he said.“I have no idea, did we win the popular vote? I don’t know, but as much information as possible should be made available.”At the Clinton event, the former first lady, secretary of state and senator was introduced by retired Iowa senator Tom Harkin and his wife Ruth, both popular figures who endorsed Clinton last summer.Harkin embraced what he said was a “narrow” victory for Clinton, even as the results were still being counted. “Hey, folks, a win is a win!” he exclaimed. Later on, Clinton’s campaign director in Iowa, Matt Paul, said there was “no uncertainty” that Clinton had won.Clinton herself stopped short of declaring victory as she took the stage, flanked by husband Bill and daughter Chelsea, before a crowd of roughly 700 supporters.“Wow, what a night, an unbelievable night,” she said. “Now, as I stand here tonight breathing a sigh of relief – thank you.”At times the cheers so deafening they drowned out Clinton’s words. It was an outright celebration, however narrow the result, of a candidate who eight years ago suffered a bruising defeat in the same state at the hands of Barack Obama.This time, she will head to New Hampshire having hit her stride – campaigning laboriously for every vote.Last time she slipped to third in Iowa behind Obama and John Edwards. As midnight approached, with 50 of the 1,683 precincts still to declare, Clinton led 49.9% to 49.6%. However, rumours began to circulate that some of the results were in dispute and that the Democratic party had failed to staff 90 caucuses, raising the prospect of an ugly clash between the Clinton and Sanders camps.In the Republican contest, it was a predictably chastening night for Jeb Bush, the candidate with all of the money and the presidential lineage who has been diminished by the taunts of Donald Trump saying he is “low energy”.Bush barely registered, in sixth place on 2.8% behind retired neurosurgeon Ben Carson in fourth and libertarian Rand Paul in fifth.But the Republican night belonged to Cruz, who called it “a victory for courageous conservatives across Iowa and all across this great nation”, vowing that the Republican nominee for 2016 “will not be chosen by the Washington establishment”.If the taming of Trump was a surprise – Cruz picked up the most votes ever in a Republican Iowa caucus – there is also a warning from history. In the last seven contested national caucuses, they have chosen the eventual nominee only three times.Donald Trump gave a rare display of humility during a brief speech at a hotel in West Des Moines.“We finished second and I want to tell you seriously I am honoured,” he said, making a point to “congratulate Ted”.After months of crowing about how he was destined to win, he immediately moved to reframe expectations, saying that he had been warned “do not to go to Iowa. You could never finish even in the top 10”.“We’re just so happy about the way everything turned out,” he added.However, the mood at Donald Trump’s party in western Des Moines went from subdued when it emerged he had been pushed into second place by Cruz, to outright downbeat when it became apparent he had been almost tied by third-place Rubio.A defiant Rubio echoed the words of Barack Obama in 2008 when he took the stage at his caucus night party in Des Moines. “So this is the moment they said would never happen. For months, they told us we had no chance,” Rubio told a raucous crowd inside a ballroom at the downtown Marriott.“They told me I needed to wait my turn. They told me we had no chance because my hair wasn’t gray enough and my boots were too high,” he said, referring to a minor media storm about his Cuban heel boots. “But tonight, here in Iowa, the people of this great state have sent a very clear message after seven years of Barack Obama we are not waiting any longer,” he added.If Rubio can lead the establishment crowd in New Hampshire, Chris Christie, John Kasich and Jeb Bush will be all but done and he may come through the middle as a youthful alternative. Cruz is deeply unpopular in his own party and Trump is diminished if not yet vanquished.“Ground game, ground game, ground game” was the reason that Cruz’s Iowa’s co- chair Matt Schultz gave for his candidate’s triumph. Cruz staffers had long been supremely confident that they had the resources on the ground to triumph and felt confident that they had done everything right.Unlike Trump, their candidate had visited all 99 counties and built up what was universally acknowledged to be the best field organisation of any candidate.The mood at the Cruz party was jubilant. A cover band played rock and country music as attendees slowly started to grasp their achievement in winning the caucuses. The crowd’s enthusiasm barely flagged as Cruz spoke for about 25 minutes to the assembled audience at the Elwell building on the grounds of the Iowa state fair.In an interview on caucus day, Cruz’s state director, Bryan English, told the Guardian that their organisation “was a model”.“It’s an organic process … go straight to people, meeting them where they are, in twos, threes, and fives, then dozens, hundreds and thousands … It’s not through paid media, not through direct mail, but through person to person relationship building.”The two casualties of the night were Martin O’Malley, who dropped out of the Democratic race, and Mike Huckabee, who suspended his Republican campaign.