In New York, the Senators win the opener, 7 – 6, then blow a four-run lead in the nitecap to lose, 7 – 5. Mickey Mantle is 5 for 8 in the doubleheader, including a homer in each game. The second homer, off Jim Hannan, is a 461-foot sky shot over the monuments into the CF bleachers. Mick follows with a sure double in the 5th but tears a hamstring muscle rounding first and will be sidelined for two weeks.

On July 8, 1966 — In New York, the Senators win the opener, 7 – 6, then blow a four-run lead in the nitecap to lose, 7 – 5. Mickey Mantle is 5 for 8 in the doubleheader, including a homer in each game. The second homer, off Jim Hannan, is a 461-foot sky shot over the monuments into the CF bleachers. Mick follows with a sure double in the 5th but tears a hamstring muscle rounding first and will be sidelined for two weeks.

Source:
Baseball Reference July 8