By 1884, Sweeney and Charles Radbourn were the Grays' two main pitchers. The 1884 season had 50 fewer scheduled games than today, and most teams got by with two-man starting rotations. Through much of April and May, Sweeney outshone the veteran and ace of the Grays, Radbourn. This created a lot of tension between the two, as Sweeney was seemingly stealing the limelight from the hobbled but proud "Old Hoss." On June 7, 1884, these tensions reached a zenith, when Sweeney took the box and struck out 19 Boston batters to set a major league record that would be tied a few times but not broken for 102 years, until Roger Clemens struck out 20 in a game in 1986. Sweeney was feted upon his return to Providence for days following his accomplishment, much to the bitter jealousy of Radbourn.