The Democrats have claimed one of the biggest scalps of the US midterms, taking a Senate seat in a previously Republican stronghold.
Kyrsten Sinema has become the first woman to be elected to the Senate in Arizona, replacing Jeff Flake.
Her race against Republican Martha McSally was so tight that her victory was not decided until Monday, after a slow count of postal ballots gave her an insurmountable lead.
Ms Sinema’s win achieves a long-held Democratic goal of making Arizona, with its growing Latino population, a competitive state.
She had made a point of not running against President Donald Trump, or even criticising his hardline immigration stance.
Ms Sinema targeted moderate Republicans and independent women by painting herself as a non-partisan problem solver.
She positioned herself as having voted to support Mr Trump’s agenda 60% of the time.
Her nearly single-issue campaign talked about the importance of healthcare and protections for people with pre-existing conditions.
Ms Sinema is said to have known Ms McSally was vulnerable because she backed the Republicans’ failed to attempts to repeal Barack Obama’s healthcare law.
She tailored her campaign for conservative-leaning Arizona, which may serve as a guide for Democrats who hope to expand the electoral map in 2020.
Ms Sinema first came to prominence as an openly bisexual Green Party activist in Phoenix, and Ms McSally criticised the Democrat over her protests against the Iraq and Afghanistan wars.
The 42-year-old was elected as a Democrat to the state legislature in 2004 and carved out a reputation as a liberal who could work with her conservative colleagues.
She was elected to congress representing a suburban Phoenix district in 2012.
Ms Sinema voted against Nancy Pelosi as the Democratic leader, supported relaxed regulations on banks and a law to increase penalties on people illegally re-entering the country.
She supported a bill making it easier to deport immigrants identified by police as gang members.
Mr Trump was quick to claim victory for his party after the midterms last week, but as vote counts continue across parts of the US the Democrats are steadily chalking up victories.
The party have taken the House of Representatives after picking up 32 seats, ending Republican control of Congress.
But while some liberals won important races in California, Colorado and Kansas, the left’s highest-profile champions fell short on election day.
Beto O’Rourke lost in his challenge to Ted Cruz in Texas, while Stacey Abrams trails her Republican opponent in the race to become governor of Georgia.
Mayor of Tallahassee and Democratic candidate Andrew Gillum, who once led in the polls in the race for Florida governor, is now awaiting the results of a recount.
President Trump has called for the recount in Florida to be called off.
(c) Sky News 2018: Kyrsten Sinema: Democrats claim historic US midterms win in Arizona