"Brazil will not accept being anyone's backyard," Brazil's left-wing President Luiz Inacio Lula da Silva declared in his election victory speech, a message squarely aimed at Washington.
Domestic elections are rarely won on foreign policy, and this one was no different. But Lula's defiance against what he has described as US interference in Brazilian affairs evoked a patriotic spirit that proved an effective campaigning tool.
It also chimed with his wider brand of politics as a former union leader: standing up to powerful figures.
Paradoxically, it seems to have earned him President Donald Trump's respect. "I like Lula, we get along well," Trump said, responding to the result. "I didn't take sides," he added, before calling the election "terrible" and "rigged".
If that sounds muddled, it is because the relationship between the two men is not straightforward. Trump did not explicitly endorse Lula's rival Flávio Bolsonaro, who has refused to recognise the result despite the Supreme Electoral Court finding no evidence of irregularities and his own party recognising the result. But Trump was a close ally of Flávio's father, the former President Jair Bolsonaro.
When I spoke to Lula at his residence about a year ago, relations had hit rock bottom. He told me he had "no relationship" with Trump, that they had never spoken, and that he had no intention of picking up the phone. Trump had recently imposed punitive tariffs on Brazil, largely as a political response to Jair Bolsonaro's coup trial, which the US president called a "witch-hunt" .
Rather than tiptoeing around Trump, as some US allies did, Lula fought back – and it paid off.
He made fiery speeches invoking Brazilian sovereignty, attacked US interference in the judicial process, and took to wearing a blue cap reading "Brazil belongs to Brazilians".
He accused the Bolsonaro family, who had lobbied for the tariffs, of being unpatriotic – a blow to a political right that so often claims patriotism as its terrain.
Even some in the agricultural lobby, typically strong Bolsonaro supporters but reliant on US trade, thought Lula had a point.
The US eventually backed down and reduced the tariffs, although they have since risen again.
The two men spoke at the United Nations and later met in the Oval Office, where Trump called the talks "very good" and Lula said he left "very satisfied".
Another indication, perhaps, that Trump likes a strongman.
So why might Trump be unhappy with the result?
Latin America has swung to the right, with Ecuador, Chile, Colombia, Argentina and Peru all electing presidents closely aligned with the Trump administration. Trump has sought to use these allies to establish US dominance in the Western Hemisphere, which he has dubbed the "Donroe Doctrine".
Christopher Sabatini, senior fellow for Latin America at Chatham House, notes that Trump thought Brazil would be the "10th and biggest prize" after Flávio Bolsonaro won the first round.
Brazil is Latin America's largest economy, and the younger Bolsonaro was expected to join Trump's "Shield of Americas" coalition against narco-trafficking.
Brazil also holds the world's second-largest reserves of rare earth minerals after China, and the US had been eyeing preferential access.
The relationship has thawed, but with four more years ahead for Lula, several issues could reignite tensions.
Brazil accused the US earlier this year of trying to cast doubt on its electoral system and denied visas to two state department officials planning to visit.
The US called this "baseless" and revoked the Brazilian ambassador's visa in response.
If Trump keeps calling this result "rigged", further diplomatic fallout is likely.
Lula has also vehemently opposed US military action in the region, from the seizure of Nicolás Maduro in Venezuela to the bombing of alleged drug-trafficking vessels.
He lambasted Washington for designating Brazil's two major gangs as terrorist organisations after lobbying from Flávio Bolsonaro, and warned of attacks on Brazilian sovereignty.
It is a sensitive subject for a political left that remembers the region's brutal 20th Century dictatorships, many backed by the CIA in the name of stopping communism.
Lula's campaign accused Meta of favouring Flávio Bolsonaro.
Meta denied this but admitted moderation issues and technical errors had wrongly removed some posts or limited their reach.
Lula's supporters responded by sharing his messages through a 10-million-strong WhatsApp group to bypass the algorithms.
Separately, the Trump administration is unhappy with Pix, Brazil's instant payment system, which has boosted the economy, but which the US sees as taking business from Visa and Mastercard.
The relationship has exposed political divisions.
In the campaign, Bolsonaro supporters waved US flags at their rallies and, in one case, an inflatable saying "Trump Nuke Brazil", while Lula and his supporters accused Flávio Bolsonaro of protecting US interests over Brazil's.
The US remains Brazil's second-biggest trading partner after China, and for now the two leaders get on.
Whether that lasts will depend on how far the US tries to intervene in Brazilian affairs, and how bullish Lula is in response.
