 Standings at start of day | Results for September 20, 1888 Game 428: Milwaukee 1, St. Paul 0 |
| Game 428: St. Paul @ Milwaukee Milwaukee 1, St. Paul 0 Milwaukee Sentinel  | Game 429: St. Paul @ Milwaukee St. Paul 4, Milwaukee 1 Milwaukee Sentinel | Game 430: Omaha @ Sioux City Omaha 3, Sioux City 1 Sioux City Journal  Game 1 | Game 431: Omaha @ Sioux City Omaha 5, Sioux City 1 Sioux City Journal  Game 2 |