On April 13, 1968 – – Looking back on his career some 30 years later, Willie Mays will recall being gunned down going from first to third exactly once: “Roberto Clemente threw me out on a bang-bang play at third. I should have remembered what a tremendous arm he had.” If Willie’s memory is correct, this was the play, as witnessed by James K. McGee of the San Francisco Chronicle: “Willie Mays, leading off the 7th, lined a single into left for the Giants’ first hit. When Willie McCovey, the next hitter, bounced a single over Donn Clendenon’s outstretched glove into right field, it appeared the dam had been broken and runs would flow. Then came the key play of the game. Mays rounded second base and slowed down to draw a throw from right fielder Roberto Clemente. Mays, either overestimating his own speed or underestimating the power and accuracy of Clemente’s arm, was thrown out trying to reach third. Maury Wills tagged him as he slid by.”

Source:
Baseball Reference April 13