July 3, 1966: Braves pitcher Tony Cloninger torches the San Francisco Giants for two grand slams and nine RBI in a 17-3 win.
After a dominant 1965 season in which he finished with a 24-11 record, 3.29 ERA and 211 strikeouts, Cloninger entered this game with only an 8-7 record. With a legendary performance at the plate, Cloninger made up for the struggles.
Atlanta chased Giants starter Joe Gibbon after only 2/3 innings -- before Cloninger had even made his first plate appearance. In Cloninger's first at-bat, he took San Fransisco reliever Bob Priddy deep to left-center field for a grand slam that gave the Braves a 7-0 first-inning lead.
The Braves led 9-0 when Cloninger came up for a fourth inning at-bat against reliever Ray Sadecki with another bases-loaded opportunity. He delivered again, taking Sadecki opposite field with two outs to stretch the lead to 13-0 and making history in the process.
Cloninger finished the game 3-for-5 with nine RBI and remains the only pitcher in MLB history to hit two grand slams in one game. He is one of only 13 players at any position to accomplish such a feat. Cloninger's RBI total is also the greatest single-game total for a pitcher in league history, being matched only by the Boston Beaneaters' Harry Staley back in 1893.
For good measure, Cloninger also dominated the Giants on the mound as well. Facing a lineup including legends like Willie Mays and Willie McCovey, Cloninger limited the Giants to seven hits and three earned runs in a complete-game performance. An ode to Cloninger's historical effort can be seen here:
Cloninger finished 1966 with career-best totals of five home runs, 23 RBI and a hitting line of .234/.261/.414.
Cloninger, now 74, has had stints as a pitching coach for the Yankees and Red Sox since retiring in 1972, and is now a player development consultant for Boston.