Logan Forsythe set up the winning hit with a one-out single against Hector Rondon (2-1). He moved up on a groundout before Alexi Amarista was intentionally walked.
Hundley then lined a clean single into center field, scoring Forsythe easily and giving San Diego its third win in four games. Dale Thayer (2-3) wiggled out of a jam in the top half to get the victory.
The game lasted 5 hours, 13 minutes, and the teams used 15 pitchers. But it wasn't even the longest game of the weekend as Arizona beat Philadelphia 12-7 in 18 innings on Saturday night.
San Diego looked poised to end the game in the 14th when it put runners on second and third with one out. But Eric Stults, batting for fellow pitcher Brad Boxberger, struck out swinging while facing a five-man infield. Chase Headley looked at a third strike to end the inning.
Chicago then wasted an opportunity to go in front. The Cubs loaded the bases with one out in the 15th, but Lake grounded into a fielder's choice that cut down Starlin Castro at home, and Murphy grounded out.
Cubs starter Chris Rusin allowed three hits and walked four in 6 1-3 innings, lowering his ERA to 2.64. The left-hander is 0-2 in his last three starts despite a 2.00 ERA.
San Diego right-hander Andrew Cashner pitched seven innings of two-hit ball against his former team. He struck out seven and walked one.
"Cash threw the ball well," Black said. "It was a great game for Cash to continue to grow as a pitcher."
NOTES: Cubs C Welington Castillo was back in the lineup after missing three games with bruised ribs. ... Cubs 1B Anthony Rizzo will remain in the No. 2 spot in the order. Rizzo, according to Sveum, has sparked the offense the last four games. "We've scored six, four, six and three," Sveum said before Sunday's game. "I'm not changing anything." ... The Padres will start Tyson Ross on Monday when they open a two-city, six-game road trip in Arizona. ... The Padres aren't sure on their starting pitcher for Wednesday. With veteran RHP Edinson Volquez designated for assignment, the Padres are juggling their rotation and considering various options.
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