 Standings at start of day | Results for September 23, 1888 Game 437: Milwaukee 7, Chicago 2 Game 1 |
| Game 437: Chicago @ Milwaukee Milwaukee 7, Chicago 2 Milwaukee Sentinel  Game 1 | Game 438: Chicago @ Milwaukee Milwaukee 9, Chicago 1 Milwaukee Sentinel  Game 2 | Game 439: Des Moines @ Sioux City Des Moines 7, Sioux City 6 Sioux City Journal  | Game 440: Omaha @ Kansas City Kansas City 13, Omaha 1 Kansas City Times  Game 1 | Game 441: Omaha @ Kansas City Kansas City 4, Omaha 0 Kansas City Times  Game 2 | Game 442: St. Paul @ Davenport St. Paul 11, Davenport 2 Quad City Times  |