By Ken Mandel / MLB.com

Mike Schmidt collected one of his 174 career stolen bases on May 31, 1975. (AP)

With Houston playing in the middle game of a three-game series, the Astros pounded out a 12-run inning against the Phillies en route to a 15-3 win. That eighth inning has held up as the biggest single inning in the park's 33 seasons.

Nothing about the game seemed odd through the first seven innings, other than perhaps Mike Schmidt stealing a base. Philadelphia scratched two runs off flamethrower J.R. Richard, the first on a fourth-inning single by Dick Allen and the second on a wild pitch an inning later.

Wayne Twitchell cruised through the first seven innings as well, allowing just four baserunners. He then began the eighth surrendering singles to Jose Cruz and Doug Rader. Rob Andrews struck out for the first out, but pinch hitter Bob Watson singled in Cruz.

Now a 2-1 game with one out and runners on first and second, manager Danny Ozark brought in southpaw Tug McGraw. Houston manager Bill Virdon countered by pinch hitting for lefty Greg Gross, now the Phillies hitting coach.

In his stead, Cliff Johnson doubled in Rader. Pinch runner Wilbur Howard also scored on the play, thanks to an error by Dick Allen.

The Astros poured it on after Roger Metzger grounded out for the second out. Cesar Cedeno was walked intentionally to put runners at the corners. Milt May and Enos Cabell each singled in a run and Cruz walked to load the bases, ending McGraw's night after allowing three hits and two walks in one-third of an inning.

Gene Garber got the ball with orders to get the final out and get the Phillies to the dugout down 5-2 with the meat of the order due up.

The longtime reliever got that final out, but not before allowing the three runners left out there by McGraw to score, as well as four more.

Rader singled in a run. Pinch hitter Ken Boswell singled in two runs. A wild pitch allowed both runners to score on a single by Howard, who had pinch run for Watson earlier that inning.

Johnson, who also entered the game in the eighth as a pinch hitter for Gross, homered for the final two runs of the inning.

The eighth-inning tally: 12 runs on 10 hits and an error. Astros 12, Phillies 2.

Philadelphia scored a run in the bottom of the eighth and Houston plated three more in the ninth on three hits, including a two-run homer by Cabell.

The defeat was the most lopsided of the season for the Phillies and the 15 runs were the most scored against the Phillies that year. The baseball gods evened the score in July, when the Phillies clubbed the Astros 14-2 on July 12. That game featured a seven-run second inning against, naturally, Richard. The 14 runs were the most scored by the Phillies that season.

Ken Mandel is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.