September 1969 against the Phillies: 5-0, 1-0, 2-0. (And prior to those three games, they beat the Cardinals 6-0. That was the only time they ever had four shutouts in a row.) They had three in a row five times, once earlier that same September, then again in May of 1970, June of 1984, May of 1985, and April of 1988. But none of those were series sweeps.