 Complete the following phrase:  In 1989, the Blue Jays new retractable roofed home, SkyDome, opened mid-season. It also marked the beginning of an extremely successful five-year period for the team. In May, management fired manager Jimy Williams and replaced him with Cito Gaston, the teams hitting instructor. The club had a dismal 1224 record at the time of the firing, but went 7749 under Gaston to win the AL East title by two games, with an 8973 record. On May 28, George Bells walk-off home run, off of Chicago White Sox closer Bobby Thigpen, marked the end of the Exhibition Stadium era. The first game at the new stadium took place on June 5 against the Milwaukee Brewers; the Jays lost 53. In the 