In a blow to Amazon, the socialist candidate Kshama Sawant appeared on Saturday to have beaten the business-backed Egan Orion for a seat on Seattle city council, despite an unprecedented financial effort from the tech giant.

Amazon is headquartered in the city. It ploughed $1.5m into the city council election through a political action committee sponsored by the Seattle Metropolitan Chamber of Commerce.

Civic Alliance For A Sound Economy dispensed about $440,000 in support of Orion and backed six other candidates considered business-friendly. In 2015, according to the New York Times, Amazon and its employees only contributed about $130,000 to city council candidates.

Sawant, a member of the Socialist Alternative party and a former tech worker, was elected six years ago as the first socialist on the Seattle council in almost 100 years. On election night she trailed Orion by 8%. But as more ballots were counted she closed the gap, and by Friday evening, with the vast majority of ballots counted, she was up by almost 4%, or about 1,500 votes.

We were up against a Goliath, there is no question about that Kshama Sawant

“We were up against a Goliath, there is no question about that,” Sawant told the Guardian. “When the billionaires have all the money, the power, the political clout on their side, it’s quite an adversary to go up against.”

King County Elections, which facilitates the ballot counting, said on Friday night there were about 2,500 votes left to count across all Seattle. Given that there are seven districts with council races, that meant there were probably fewer than 1,000 ballots left to count in Sawant and Orion’s race.

Washington state runs a vote-by-mail system, which means it can take days to achieve a final count. In the past, more late voters have favoured the far left.

Sawant thanked more than 1,000 volunteers who she said knocked on more than 200,000 doors. She also said she believed the funding and support her opponent received from Amazon and other corporations could have backfired.

“All of this clarified to people that big business is not on our side,” she said. “This mythology that, ‘Oh if only we behaved nicely and we brought big business to the table, things would work out.’ Well that’s been blown to smithereens. They are not on our side and in fact they will use every dollar that they can to try and crush the movement.”

Orion, an LGBTQ community leader and advocate for small businesses who considers himself a progressive liberal, has said he considered the funding from Amazon unnecessary and largely a distraction.

Four other candidates endorsed by the Civic Alliance For A Sound Economy also seemed set to lose. Phil Tavel, Heidi Wills, Mark Solomon and Jim Pugel trailed their opponents by at least 6%, with Solomon down by about 20%. Two candidates endorsed by the Pac, Alex Pedersen and Debora Juarez, had substantial leads.

A win for Sawant would give her a third term. She has been a fierce critic of the influence of big business on Seattle, and helped lead the push last year for the head tax, a per-employee tax on large corporations that was repealed a month after passing unanimously.

On Saturday, Sawant said she planned to continue her battle for a tax on big business. Orion does not support the head tax.