Pirates 4, Reds 1: James McDonald threw eight scoreless innings and the Pirates jumped on Reds starter Bronson Arroyo early as host Pittsburgh reached the .500 mark for the first time since April 10.
The Pirates have won a season-high four straight games. Cincinnati lost for just the second time in its last 10 games.
McDonald (4-2) held the Reds to five hits and one walk, striking out five. He was unable to finish his first complete game in the majors, leaving after throwing 103 pitches.
Arroyo (2-3) lasted only four innings, allowing four runs on eight hits.
Pedro Alvarez hit an RBI double off the wall in the left-field corner and scored on Garrett Jones' single in the first to stake McDonald to an early lead.
Neil Walker added to the lead with an RBI double inside the first base bag in the second and Rod Barajas' RBI single in the third made it 4-0.
Chris Heisey's RBI single against Tony Watson in the ninth broke up the shutout, but Joel Hanrahan came in to record the final out for his 12th save.
GAME NOTEBOOK: McDonald has lost just one of his last eight starts and improved to 5-1 against Cincinnati. … Arroyo is winless in his last four starts. He dropped to 6-7 against his former team. … Pittsburgh OF Jose Tabata started and batted leadoff despite being listed as questionable with cramps in his left leg.