Mato Grosso's Senate race for first place remains tightly contested because voters select two senators in October 2026 and recent polling shows a fragmented field with no dominant frontrunner. Real Time Big Data surveys from mid-August place Mauro Mendes and Janaína Riva at the top of first- and second-vote intention, followed by Carlos Fávaro, José Medeiros and Pedro Taques, while Antônio Galvan, Margareth Buzetti, Coronel Darwin and others trail. Party conventions in August finalized a field of roughly ten registered candidates, keeping probabilities compressed as traders weigh name recognition, regional bases and potential alliances. Late-campaign factors such as additional polling releases, coalition alignments or shifts in voter turnout among agricultural and interior regions could create separation before election day.