In the course of Pittsburgh’s 8 – 0 shellacking of the lowly New York Mets, in which the latter’s total of 4 hits is equaled by Roberto Clemente, the Pirate right fielder hits one ball, leading off the 4th, that the young Ron Swoboda, playing left field for the Mets that day, will recall, some thirty years later, as “the hardest ball I ever saw hit.” Bucs beat writer Les Biederman concurs: “The first hit by Clemente was one to remember. It started out on a line toward the right-center fence and came within inches of clearing the wall at the 436-foot sign. It bounced off the wall right back into rookie Billy Murphy’s hands.” “The ball got there so fast, and bounced back to Murphy so hard,” notes Dick Young of the New York Daily News, “that the speedy Roberto got only two bases.” “But,” adds Biederman, “the blast caused a rumble through the stands and no doubt unnerved Jack Fisher.”

On May 1, 1966 — In the course of Pittsburgh’s 8 – 0 shellacking of the lowly New York Mets, in which the latter’s total of 4 hits is equaled by Roberto Clemente, the Pirate right fielder hits one ball, leading off the 4th, that the young Ron Swoboda, playing left field for the Mets that day, will recall, some thirty years later, as “the hardest ball I ever saw hit.” Bucs beat writer Les Biederman concurs: “The first hit by Clemente was one to remember. It started out on a line toward the right-center fence and came within inches of clearing the wall at the 436-foot sign. It bounced off the wall right back into rookie Billy Murphy’s hands.” “The ball got there so fast, and bounced back to Murphy so hard,” notes Dick Young of the New York Daily News, “that the speedy Roberto got only two bases.” “But,” adds Biederman, “the blast caused a rumble through the stands and no doubt unnerved Jack Fisher.”

Source
Baseball Reference May 1