Los Angeles Dodgers rookie Fernando Valenzuela finally loses a game, 4 – 0, to the Philadelphia Phillies. He is now 8-1 and his earned run average increases to 0.90.

On May 18, 1981 —  Los Angeles Dodgers rookie Fernando Valenzuela finally loses a game, 4 – 0, to the Philadelphia Phillies. He is now 8-1 and his earned run average increases to 0.90.

Source:
Baseball Reference May 18