Don Robinson (11-7) pitched a five-hitter for his third successive complete game and fourth of the season.
Hoyt even pitched a five-hitter in Chicago's 2-1 opening-game victory.
Bruce Hurst (8-7) pitched a five-hitter for his fifth complete game, striking out six and walking three.
Curt Young (1-0) pitched a five-hitter for the Athletics, who had dropped their first five games.
Lieber (7-10) pitched a five-hitter for his second complete game of the season.
Boyd (3-2) pitched a five-hitter, walked none and struck out eight.
Mike Morgan (9-5) pitched a five-hitter, struck out three and walked two for his fourth complete game of the season.
He pitched a five-hitter for his third big league shutout, struck out a career-high seven and walked one.
Tom Candiotti (3-1) pitched a five-hitter, struck out nine and walked two.
He pitched a five-hitter and struck out six for his second complete game this season.