This one started out so promisingly as Johnny Cueto struggled to start the game. Ben Zobrist was hit by a pitch and advanced to second on a wild pitch. Jason Heyward drew a walk to give the Cubs two runners with no outs, but the next three batters were retired without a run crossing the plate.
Mike Montgomery was not sharp. Chase d'Arnaud hit a solo shot to give the Giants an early lead. Monty walked Andrew McCutchen around retiring Belt and Posey for two outs in the frame. Brandon Crawford hit a ball back up the middle that Monty was unable to glove. Gorkys Hernandez doubled and an error by Ben Zobrist allowed a pair of runs to score and Hernandez to reach third. Steven Duggar singled back up the middle to make it a 4-0 Giants lead before Montgomery finally ended the inning.
Cueto pitched around a pair of two out singles in second inning, but the score remained 4-0 heading into the bottom of the second. Monty recovered to retire the side in order. Heyward hit a solo shot to get the Cubs on the board in the third inning, but it looked like Cueto settled into the game retiring the side afterwards. It looked like Montgomery would give the run right back in the bottom half of the third. McCutchen and Posey singled to start the frame, and McCutchen advanced to third on Brandon Crawford's fielder's choice. A Hernandez groundout in the infield couldn't drive in McCutchen, who remained planted at third as Duggar grounded out to end the frame.
The Cubs were able to run up the pitch count against Cueto, but the score remained 4-1 heading into the fifth inning. Cueto walked Jason Heyward to start the inning, and Kris Bryant launched a home run to dead center to make it a 4-3 ballgame. Anthony Rizzo walked to keep things going, but again the Cubs went quietly afterwards. Montgomery kept the Giants off the board for another frame to turn it into a battle of the bullpens in the sixth inning.
The Giants combination of Ty Blach and Reyes Moronta to keep the Cubs down one after six innings. Randy Rosario pitched around a couple of two out singles to keep the Cubs within one. Tony Watson was the next Giants reliever and Javier Báez tied the game with one swing. That was the last time a Cubs hitter reached second base in the game. Watson pitched through the seventh. Mark Melancon pitched the eighth inning and the Giants closer Will Smith took two innings. Derek Rodriguez took the ball in the eleventh inning and put three more zeroes on the board. It would be enough to get the Giants another win.
Pedro Strop and Justin Wilson combined to get into the eighth inning. Luke Farrell pitched around a leadoff walk in the ninth inning and put another zero on the board in the tenth inning. Brandon Morrow looked good in his return in the tenth inning, but that left James Norwood as the only available arm once the game hit 11. Norwood struck out Crawford in his big league matchup and managed to throw an inning and two thirds. The Giants, however, mercifully ended the game in the thirteenth inning with some two out magic. Brandon Belt walked and McCutchen singled to give the Giants a scoring chance. Posey hit a single into the outfield grass to drive in the winning run. The Cubs dropped their first series since the dreadful Reds sweep.