As Alvarez's 450-foot blast in the sixth inning disappeared, Astros starter Framber Valdez jumped and wildly screamed in the dugout as fans in the crowd of 42,948 went into a frenzy waving their orange rally towels.
Baker finally got his first title in his 25th season as a manager, the past three since being hired by the Astros to help the team regain credibility after the sign-stealing scandal that cost manager A.J. Hinch and general manager Jeff Luhnow their jobs, and made Houston the most reviled team in baseball.
The 73-year-old Baker, who had been to the World Series twice before as a skipper, is the oldest championship manager.