The Pirates stayed one step ahead of the Cubs most of the night, and 17 pitches from relief ace Felipe Rivero got him through 1 2-3 innings to close out the game for a 4-3 victory.
Clinging to a 4-3 lead late again, Clint Hurdle went to Rivero with one out in the eighth, after Ian Happ had doubled off Daniel Hudson. Rivero issued a walk to Kris Bryant, but Miguel Montero lined out to right and Addison Russell grounded out to end the inning. Rivero needed just eight pitches to retire the side in the ninth and nail down his third save of the season.
Rivero has pitched two days in a row, but the relatively stress-free outing at least leaves the door open to his availability in a rubber match Sunday.
The Pirates took a 2-0 lead in the first when Gregory Polanco, riding an 0-for-12 skid, lined one over the Clemente Wall for a two-run homer.
The lead held at two until Jake Arrieta himself smacked a two-run homer to left, tying the game in the fifth.
The Pirates quickly retook the lead in the bottom of the fifth, when Jordy Mercer doubled, moved up on a wild pitch and scored on Adam Frazier’s single. An intentional walk to Polanco and a hit-by-pitch for David Freese chased Arrieta after just 4 2-3, but Brian Duensing got Josh Bell to fly out with the bases loaded.
Andrew McCutchen clobbered a hanging curve from Justin Grimm for a solo homer in the sixth for a 4-2 lead. That proved important when Russell led off the seventh with a homer off Ivan Nova to pull within 4-3.
Jason Heyward reached third in the seventh, but Nova escaped without further damage.
Nova finished with six strikeouts and two walks, allowing the three runs on six hits in seven innings. He’s pitched at least six innings in all 14 of his starts in 2017. The last Pirates pitcher to run such a streak was Eddie Solomon in 1981.
Polanco added a double, going 2-for-3. Russell and Anthony Rizzo were both 2-for-4 for the Cubs.
Jameson Taillon makes his second start since undergoing surgery for testicular cancer, squaring off with John Lackey on Sunday.