The win moved the Reds a season-high 30 games above .500 and lowered their magic number to clinch the National League Central to 8, combined with a Cardinals loss, with 18 games left on the schedule.
"It was a nice sweep, and we're one step closer to winning the division," said Reds manager Dusty Baker. "We finally reached 30 [games above .500], and now you set a new goal and try to get 35. I was proud of these guys. They played outstanding the whole series against a very tough Pirate team."
The Reds have been 29 games above .500 four different times this season, but the fifth attempt proved to be the charm as Reds starter Homer Bailey outdueled Pirates ace A.J. Burnett to earn his 11th win of the season.
Prior to Wednesday's outing, Bailey hadn't earned a victory since Aug. 10, despite giving up two earned runs or fewer in four of his past five starts.
"Homer's been dealing his last four or five starts and [didn't have] a whole bunch to show for it," Baker said. "We wanted to hold that one, big time. He's lost the last three or four where we didn't hold the lead."
Bailey nearly got the short end of the stick again Wednesday and found himself in a sixth-inning jam with the go-ahead run on third.
Bailey had held the Pirates to just one run on five hits -- three of which came in the third inning -- when Alex Presley slapped a one-out triple down the right-field line.
Two pitches later, the Pirates attempted to execute a suicide squeeze that the Reds snuffed out from the get-go. Presley took off for home as Bailey delivered to Clint Barmes.
Suspicious of the steal, Bailey got the sign to pitch out but slipped on the mound and delivered a low and away pitchout, and Barmes whiffed on the bunt attempt.
"I still came close to it," Barmes said. "But when I lunged, my top hand came off the bat, and the barrel dipped."
Catcher Ryan Hanigan snagged the ball after a slight juggle, blocked the plate with his left leg and applied the tag. Barmes then flied out to center to end the inning.
"I think all of that credit goes to Dusty and [bench coach Chris] Speier over there," Bailey said. "As soon as I saw the sign, I tried to get it higher and more away. [Hanigan] has been a warrior out there. He blocked the plate, did a great job. He had chalk and dirt all over his face. Most of the credit goes to them. I just threw it."
Baker called the play "the difference in the game," and the momentum swing went the Reds' way. Ryan Ludwick doubled to left to start the bottom half of the frame and made it to third on Jay Bruce's flyout to deep center.
Scott Rolen then launched a sacrifice fly deep enough to left field to plate Ludwick for the eventual game-winning run.
"The key to the game was we executed well," Baker said.
Bailey lasted just one more 1-2-3 inning in the seventh before Baker turned to his already depleted bullpen to round out the game.
The Reds were resting closer Aroldis Chapman due to fatigue and wanted to avoid using Jonathan Broxton and Sean Marshall, who both pitched back-to-back days.
So with the Reds' top three closer options unavailable, the ball fell into the hands of rookie J.J. Hoover, who answered the call with an "outstanding" finish, according to Baker.
Hoover gave up a lone two-out single in the ninth before striking out Jose Tabata to complete the sweep and earn his first save in the Major Leagues in his first opportunity.
"This is awesome," Hoover said. "I've never really played on a winning team in the Minors, and to come up here and be in the pennant race in the big leagues in my rookie season is a lot of fun. This clubhouse has great chemistry, and I think everyone's pulling for everybody, and we're all trying to win the division."
The Reds took a large step in that direction this week and are now even closer to clinching their second NL Central crown in three seasons.