Right-wing senator Flávio Bolsonaro upset President Luiz Inácio Lula da Silva in the first round of Brazil's general election, triggering a rally for a couple of U.S.-listed stocks on Monday.

Shares of online retailer MercadoLibre, which counts Brazil as its largest market, jumped 6.5% in premarket trading. Brazilian neobank Nu surged 12%.

Oil major Petroleo Brasileiro, commercial bank Itaú Unibanco, miner Vale, and brewer Ambev were also surging. The four stocks are all available to U.S. investors via their American depositary receipts.

Given how broad Monday's rally was, an exchange-traded fund may be an even better way to invest in Brazil. The iShares MSCI Brazil ETF surged 13% ahead of Monday's opening bell.

The moves higher came after Bolsonaro, an ally of U.S. President Donald Trump and the eldest son of Brazil's imprisoned former President Jair Bolsonaro, received 47.3% of votes in Sunday's general election.

Incumbent Lula, who had been ahead in pre-election polls, got a 44.8% vote share. As neither candidate reached the 50% needed for an outright victory, there will be a runoff election on Oct. 25.

Bolsonaro had positioned himself as the free-market candidate ahead of the election, promising to introduce a public debt ceiling and cut spending.

The Trump administration imposed a 25% tariff on certain Brazilian goods in July, following a yearlong investigation into what officials called unfair trade practises. Lula called that "a lamentable milestone" in the history of U.S.-Brazil trade relations.