After 5,687 consecutive contests take place during the day at the Chicago Northside ballpark dating back to 1914, the first official major league night game is played at Wrigley Field, with the hometown Cubs taking a 6-4 decision from the Mets. The historic event was scheduled for last night, but the contest against the Phillies was rained out after the third inning.

On August 9, 1988 — After 5,687 consecutive contests take place during the day at the Chicago Northside ballpark dating back to 1914, the first official major league night game is played at Wrigley Field, with the hometown Cubs taking a 6-4 decision from the Mets. The historic event was scheduled for last night, but the contest against the Phillies was rained out after the third inning.

Source:
Baseball Reference August 9
National Pastime
Retro Sheet
Hall of Fame
SABR Games Project
Replay The Game