In 1990, Stewart was 22–11 (his fourth straight 20-win season and tied for 2nd in the majors) with a 2.56 ERA in 36 starts. He led the league in innings pitched (267), complete games (11) and shutouts (4) while being third in ERA and finishing third in the Cy Young voting. On June 29, he no-hit the Toronto Blue Jays, at SkyDome, the first no-hitter by an African American since Jim Bibby in 1973. That same day, Fernando Valenzuela of the Dodgers no-hit the St. Louis Cardinals at Dodger Stadium – the first time in Major League history that no-hitters had been thrown in both leagues on the same day. The A's won their third straight pennant, beating the Boston Red Sox in the American League Championship Series, and Stewart was named the ALCS MVP going 2–0 with a 1.13 ERA. Stewart got the start in Game one of the 1990 World Series for the heavily favored A's against the Cincinnati Reds. However, Eric Davis hit a two-run home run off him in the first inning and he only lasted four innings as the Reds pulled off the upset. He pitched better in game four, allowing only one earned run while pitching a complete game, but the Reds won the game and finished off a sweep of the series. Despite being the losing pitcher in games 1 and 4 Stewart had a 2.77 ERA in the 1990 World Series.