With the legalisation of professionalism in the summer of 1885, Roberts and his teammates all became professional players in 1885–86, and proceeded to win both the Birmingham and Staffordshire cups. Albion lost to Blackburn Rovers (via a replay) in the 1886 FA Cup Final, the first of three successive FA Cup Finals in which Roberts played. He received another runners-up medal the following year as Albion were defeated 1–0 by rivals Aston Villa in the 1887 final. During the cup run he is credited with scoring a goal from a long kick downfield against Derby Junction. Twelve months later he helped his team to victory in the 2–1 win over Preston North End in the 1888 final. His performance for Albion was described as "most remarkable" by The Times, while The Standard said that his keeping was "brilliant all through the game". Later that year Roberts played in the "Championship of the World" match, which pitted the English FA Cup holders against the winners of the Scottish Cup. Albion lost the game 4–1 to Renton at Hampden Park.