Denny McLain wins 12 – 1 at Washington, as the Tigers pass the first-place Orioles. Detroit will remain in the lead for the rest of the season.

On May 10, 1968 — Denny McLain wins 12 – 1 at Washington, as the Tigers pass the first-place Orioles. Detroit will remain in the lead for the rest of the season.

Source:
Baseball Reference May 10