Pirates 8, Cubs 4: Michael McKenry hit a three-run homer and Garrett Jones collected three RBIs as visiting Pittsburgh broke out late and cruised to a series win over Chicago.

Rookie Starling Marte added a solo home run, Andrew McCutchen scored a pair of runs and Jeff Karstens pitched five strong innings for Pittsburgh, which has won six of eight to stay in the playoff hunt.

Clinging to a 2-1 edge after seven innings, Pittsburgh broke out for five runs in the eighth against right-hander Shawn Camp. Jones, pinch hitting for newly acquired Gaby Sanchez, sent a single into left to chase home Josh Harrison and McCutchen, and McKendry followed a single from Travis Snider by taking a 1-0 sinker deep into the stands in left-center for his 10th homer.

The Cubs grabbed the lead on Starlin Castro’s solo home run in the first inning but the Pirates wrested control away in the third. Marte led off and drove a first-pitch fastball into the basket above the left field wall for his second career blast.

Pittsburgh scored the go-ahead run later in the frame when Chicago starter Travis Wood balked with McCutchen on third to force in the run.

Karstens (4-2) allowed one run and three hits while walking one and striking out four to earn the win and five relievers combined to work the final four frames.

The Cubs scored three times in the ninth inning on an RBI triple from Jeff Baker and Welington Castillo’s two-run blast.

Wood (4-7) took the loss, getting charged with two runs and three hits in five frames. The left-hander struck out six and walked three in his fourth straight setback.

GAME NOTEBOOK: Cubs 2B Darwin Barney missed the game after getting hit in the side of the head by a pitch in Tuesday’s contest. Baker started at second. … Chicago on Wednesday optioned RHP Casey Coleman to Triple-A Iowa and recalled RHP Chris Volstad and RHP Alberto Cabrera. … 1B Sanchez made his debut for the Pirates, batting cleanup and going 0-for-2. … Snider, who was also making his Pittsburgh debut, went 2-for-5 with a run scored.