Washington, Aug 13 Teflon \'Donald\', as \'Donald Trump\' has come to be called, and self-proclaimed socialist Bernie Sanders have upended the US presidential race with their surprise surge against establishment favourites in both Republican and Democratic parties.

Defying media pundits who had predicted that the Trump campaign would unravel after his dustup with a female host during the first presidential debate on Fox News, the real estate mogul Trump tops the Republican field with 22 percent among likely caucus-goers in Iowa, the first nominating state, in a new poll.

He is also seen as the candidate seen as best able to handle top issues including the economy, illegal immigration and terrorism, according to a CNN/ORC poll in the state.

Trump is most cited as the one with the best chance of winning the general election and, by a wide margin, as the candidate most likely to change the way things work in Washington.

Retired neurosurgeon Ben Carson follows Trump in overall preference with 14 percent, bumping Wisconsin Governor Scott Walker, who had held the top spot in most recent public polling in Iowa, down to third place with 9 percent. Walker is nearly even with a slew of other candidates.

Texas Senator Ted Cruz follows the top three at 8 percent, with former HP CEO Carly Fiorina and former Arkansas Governor Mike Huckabee both at 7 percent. Former Florida Governor and establishment favorite Jeb Bush is tied at 5 percent with senators Rand Paul and Marco Rubio.

The rest of the field stands at 3 percent or less with Louisiana\'s Indian-American governor Bobby Jindal polling about two percent.

On the Democratic side, Vermont senator Bernie Sanders has for the first time pulled ahead of former Secretary of State Hillary Clinton in New Hampshire, the first primary state, according to a new poll. Sanders topped Clinton with 44 percent compared to her 37 percent support among likely Democratic primary voters, according to a Franklin Pierce University/Boston Herald poll.

Sanders has been gaining momentum as he generates enthusiasm among the Democratic Party\'s progressive base but until now he has still trailed Clinton in every early state poll, CNN said.

Clinton continues to enjoy more than double Sanders\' support in national polls, though that polling has also shown Clinton\'s vulnerabilities as voters question her honesty and trustworthiness.

Vice President Joe Biden, who is reportedly still considering whether to enter the fray, would start with a 9 percent base of support in New Hampshire if he decided to run, according to the poll.

The bottom three candidates, former Virginina Senator Jim Webb, former Maryland Governor Martin O\'Malley and former Rhode Island Governor Lincoln Chafee, resonated with one percent or less of likely Democratic primary voters.

Trump, Sanders upend US presidential race