Cubs right-hander Pedro Strop (0-1) walked two batters in the eighth and recorded only one out before being replaced by left-hander James Russell. Russell immediately walked Pedro Alvarez to load the bases and Martin followed with a fly ball to right field that made it 7-6.
Castro hit a game-tying three-run homer in the third and a solo shot in the sixth against Morton for his first career multi-homer game.
Cubs starting pitcher Edwin Jackson gave up six runs on nine hits in 4 2-3 innings. Jackson struggled with his command, walking four (one intentional) and hitting a batter. Pirates starter Charlie Morton didn't fare much better allowing five runs on eight hits in six innings.
Jackson's troubles began on the game's first pitch with a lead-off double by Starling Marte. It sparked a four-run inning and nine Pirates batted in the first.
Bonifacio's two-out single to center field in the second inning scored Ryan Sweeney from second base to cut the Pirates' lead to 4-1.
Two-out walks hurt Jackson in the fourth. Jackson put Marte and Travis Snider on base to bring up McCutchen, who came through with an RBI single to put the Pirates back ahead, 5-4. Ishikawa's triple in the fifth scored Martin, who doubled to start the inning, and extended Pittsburgh's lead to 6-4.
Cubs manager Rick Renteria was ejected in the top of the ninth inning by home plate umpire Jeff Nelson for arguing balls and strikes. It was Renteria's first ejection
NOTES: Renteria said the Cubs are sticking with the five-man rotation as constructed meaning RHP Carlos Villanueva will stay in the rotation and not move back to the bullpen. . Cubs president of baseball operations Theo Epstein said he didn't have a problem with top prospect Javier Baez's recent ejection at Triple-A Iowa labeling it a ''great development experience'' for the 21-year-old shortstop. . Epstein said the Cubs are being cautious with Double-A Tennessee OF prospect Jorge Soler (sore right hamstring) by putting him on the seven-day disabled list. Soler aggravated his hamstring during the first minor league game of the season while running to second base on a double. . On the 40th anniversary of Hank Aaron hitting the 715th home run of his career to set an MLB record, Pirates manager Clint Hurdle fondly remembered the moment. ''I wasn't watching at the start and my dad tried to tune in the radio because we were in Florida,'' Hurdle said. ''We listened to a lot of the games on radio. As it turned out, it was a pretty magical moment.''