The Brazilian talent factory is always working hard and the latest star outside the production line looks to be Fluminense midfielder Matheus Martinelli.According to Globe Esporte, scouts from both Manchester United and Arsenal have kept a close eye on the teenager, who first made his senior debut in November 2020 and is already an important part of the Fluminense lineup.Martinelli's stock will only rise, so it's time to get to know him.At home at the base of Fluminense's midfield, Martinelli's bread and butter pass around…