With Jesse Chavez on the mound in relief, Brandon Phillips walked and Jay Bruce reached on an infield hit to put runners on first and second to begin the eighth.
With Phillips and Bruce running on the pitch, Edwin Encarnacion lined softly to Jack Wilson at shortstop.
"I saw it coming," said Pirates second baseman Freddy Sanchez. "Both runners were going. When Jack caught the ball, Bruce was standing on second base. I knew it was going to be a triple play."
Wilson threw to Sanchez at second to retire Phillips, and Sanchez threw on to first baseman Adam LaRoche to retire Bruce to complete the triple play.
"I've never seen a triple play, at any level," said Pirates outfielder Brandon Moss. "That was pretty cool."
It was the first triple play for Pittsburgh on the road since July 31, 1968, in, coincidentally, Cincinnati at Crosley Field.
The Bucs amazingly turned the feat twice in '68 at Crosley, also accomplishing it on April 18.
The last time the Pirates turned a triple play was Aug. 10, 1993, vs. St. Louis when Gregg Jefferies hit into a triple play, Jay Bell to Carlos Garcia to Kevin Young.
The Reds had not hit into a triple play since April 21, 2007, vs. Philadelphia, when catcher David Ross grounded into a 5-4-3 triple play.
"It's usually a line drive or something," said Pirates manager John Russell. "It's been a long time since I've seen one."
Jeff Wallner is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.