On May 26, 1959, Mantilla led off the 13th inning by reaching first on Don Hoak‘s throwing error, ruining Harvey Haddix‘s perfect game, and eventually scoring the game’s only run. A utility man for six seasons with the Braves, he was selected by the Mets in the expansion draft and became their most regular third baseman in 1962, hitting .275 with 11 home runs. The Red Sox traded three players to acquire him the following winter, and in Fenway Park his offensive production jumped considerably. He hit a career-high .315 in 1963 and belted 30 homers in 1964, 19 more than his previous best. Playing second base in 1965 he drove in 92 runs, but his average plummeted to .219 in 1966 after he was traded to Houston.