The Brazilian government on Tuesday congratulated Gustavo Petro on his election as neighbouring Colombia's first leftist president, though Brazil's far-right leader Jair Bolsonaro was yet to comment.
Polls show Bolsonaro lagging behind leftist former president Luiz Inácio Lula da Silva ahead of a two-round presidential poll in October.
In a brief statement, the Foreign Ministry in Brasilia said it looked forward to "the continuity and deepening of bilateral relations" with Colombia under Petro.
Bolsonaro, a former Army captain and fervent anti-leftist, has not reacted to the Colombian election outcome.
His son, lawmaker Eduardo Bolsonaro, tweeted a map after Sunday's vote with the communist hammer and sickle symbol marking leftist-governed countries Argentina, Chile, Bolivia, Peru, Venezuela and now also Colombia.
It was topped with the observation: "The responsibility of every Brazilian voter only increases. It is no longer 'only' for Brazil but for all the region."