Gerrit Cole (6-3) spun 5 2/3 innings of one-run ball for Pittsburgh, while four relievers didn't allow a hit over the final 3 1/3 frames. Jason Grilli struck out two in the ninth to nail down his ninth save of the season.
Cole allowed just the one run on four hits and a pair of walks while striking out six to win his third straight decision. The Pirates, who took the series opener 10-3 on Monday, have won three straight and five of six.
Jesse Hahn (0-1) was roughed up for four runs on six hits in 3 2/3 frames in his major league debut.