Andrew McCutchen's homer in the bottom of the seventh inning was the difference as Pittsburgh edged Cincinnati, 6-5, in the opener of a three-game series.
McCutchen finished with two hits and three RBI, while Neil Walker drove in a pair of runs for the Pirates, who have won three of four.
Tony Watson (1-0) gave up two runs in the top of the seventh, but still picked up the win in relief. Jason Grilli stranded two in the ninth to close out the game and earn his fourth save.
Brandon Phillips homered twice and Devin Mesoraco knocked in two runs for the Reds, losers of three straight games.
J.J. Hoover (0-1) was charged with the loss after giving up McCutchen's deciding blast while recording only one out in the seventh.
"He one of the best players in the league," Reds manager Dusty Baker said of McCutchen.
McCutchen greeted Hoover rudely, as his second home run of the year just cleared the wall in left to give the Pirates a 6-5 edge.
"I was able to get a good pitch and hit it out," McCutchen said simply.
Mark Melancon turned in a placid eighth inning, but Grilli made it tough on himself in the ninth.
He gave up a one-out single to Shin-Soo Choo, then Chris Heisey reached first on a fielder's choice ahead of a walk to Joey Votto which left two on. However, Phillips fanned swinging to end the game.
Russell Martin's two-out RBI single in the home first put the Bucs on the board, but a leadoff solo shot from Phillips in the second evened the game.
Pittsburgh plated four in the home half, thanks to consecutive two-run singles by Walker and McCutchen, to take a 5-1 lead.
In the Cincinnati fourth, Jay Bruce hit a leadoff single, moved up on a Jack Hannahan base hit and later crossed the plate on a Mesoraco groundout.
Mesoraco's double in the sixth plated Zack Cozart to pull the Reds within 5-3, then a one-out walk to Heisey in the seventh preceded a two-run blast from Phillips off Watson which tied the game.
Bucs starter A.J. Burnett allowed six hits and three runs with eight strikeouts and three walks over six innings. Reds counterpart Mike Leake also lasted six frames, giving up 10 hits and five runs ... Pirates left fielder and leadoff hitter Starling Marte extended his streak of multi-hit games to six straight, going 12-for-25 in that span, and has reached base safely in nine of Pittsburgh's first 10 games ... Prior to the contest, the Bucs recalled pitcher Bryan Morris from Triple-A Indianapolis and designated pitcher Chris Leroux for assignment.