Reds 6, Pirates 5: Brayan Pena ripped the go-ahead RBI single with two outs in the eighth inning as host Cincinnati overcame a four-run deficit to record its eighth win in 11 games.Devin Mesoraco belted a solo homer off Tony Watson (5-1) to ignite a string of five consecutive hits with two outs in the eighth inning. Ramon Santiago added an RBI single to forge a 5-5 tie before Pena stepped up as a pinch hitter and deposited a 1-1 fastball into center field to plate Chris Heisey.Santiago had an RBI double and joined Billy Hamilton with three hits and a run scored for the Reds, who have claimed eight of the 11 meetings versus Pittsburgh this season. Curtis Partch (1-0) picked up the win despite issuing three walks in one inning of work while Aroldis Chapman struck out the side in the ninth to secure his 20th save.Pedro Alvarez belted a three-run homer and Andrew McCutchen also went deep in the fourth inning for the Pirates. McCutchen added a double to lead off the sixth and came around to score on Russell Martin's single as Pittsburgh bolted out to a 5-1 advantage.Hamilton avoided a tag to reach on a bunt in the first and came around to score when Zack Cozart ripped a first-pitch fastball from Jeff Locke into left field for a double. McCutchen answered with a solo shot in the fourth, and Neil Walker and Martin quickly got aboard before Alvarez deposited a 2-0 fastball from Mat Latos over the wall in right field.GAME NOTEBOOK: Latos yielded four runs - three earned - on three hits in five innings before departing with lower back spasms. ... McCutchen has belted 18 homers versus the Reds since 2009, the most by any player against the club in the majors. ... Cincinnati INF Skip Schmuaker was placed on the seven-day concussion disabled list prior to the contest. The team recalled OF-1B Donald Lutz from Triple-A Louisville to fill the available roster spot.