Pirates 6, Reds 5: Ike Davis and Andrew McCutchen homered and Neil Walker delivered a game-winning RBI single in the ninth as Pittsburgh took the opener of a four-game series with visiting Cincinnati.

McCutchen went 3-for-3 and scored twice and Walker also had three hits for the Pirates. Walker's looping liner with two outs in the ninth twisted second baseman Brandon Phillips around, and catcher Devin Mesoraco couldn't handle right fielder Jay Bruce's throw to the plate as Russell Martin slid home to end it.

Phillips, Mesoraco and Todd Frazier each had three hits for the Reds, who lost for only the second time in their last six games. The rest of the team was just 2-for-23.

Billy Hamilton scored on Phillips' grounder in the first and Frazier made it 2-0 with an RBI double in the third, but Davis put the Pirates on top in the fourth when he blasted Mike Leake's first pitch into the right-field seats for a grand slam and a 4-2 lead. Hamilton's sacrifice fly in the seventh chopped the deficit in half, and Bruce and Mesoraco each knocked in runs in the eighth to help the Reds regain the lead.

The lead didn't last long as McCutchen led off the bottom of the eighth with an opposite-field blast off Manny Parra, and the Pirates threatened to do more damage before J.J. Hoover (1-2) struck out Jordy Mercer with the bases loaded to end the inning. The Reds strung together a pair of two-out singles in the ninth before Jared Hughes (1-0) got out of the jam, and a pair of one-out walks from Hoover set up Walker's game-winner.

GAME NOTEBOOK: Davis, who also hit a grand slam against the Reds on April 5 while with the Mets, is the first player in major-league history to hit grand slams for two different teams in April and the third to hit two grand slams against the same team in a season while playing for different teams, according to Elias Sports Bureau. … Mesoraco extended his career-best hitting streak to 10 games and boosted his average to 541. … Leake allowed four runs on eight hits over seven innings and Pirates starter Francisco Liriano gave up five runs (four earned) on seven hits over seven frames, but neither factored in the decision.