Arizona (78-72) has beaten Chicago (78-71) in five of their six meetings over the past two weeks, including the first two games in Phoenix this weekend.
The Diamondbacks won three out of four games in Chicago last week.
They are coming off Saturday's dramatic 7-6 win behind run-scoring singles by Emmanuel Rivera and Gabriel Moreno with two outs in the 13th inning.
Moreno ended the game with his hit coming on a 0-2 count from Hayden Wesneski.
Evan Longoria scored from third base, barely beating the throw to home plate and sliding headfirst.
Longoria admitted he did not look at third-base coach Tony Perezchica when rounding to home from second base, where he was after walking and moving there on Rivera's infield single.
"It's the 13th inning of this game, and we've been plugging away in extras," Longoria said. "I figure if I'm out at home, I'm out at home. I tried to end it right there."
Arizona trails Chicago by a half-game in the wild race.
The Diamondbacks are tied with the Cincinnati Reds (78-72) for the third and final wild card spot.
The Miami Marlins (77-72) trail Arizona and Cincinnati by a half-game.
Only 11 games will remain for Arizona in the regular-season schedule after Sunday's game.
"I told the guys, 'Give me everything you got. Do it for me, do it for the coaches who are training you and talking to you, do it for your brother sitting next to you.'" Arizona manager Torey Lovullo told reporters. "You can't lose if you give your absolute best. Everybody's tired, everybody's cranky, but that fatigue is easy to overcome if you want it bad enough."
"Sometimes I say things inspiring," he said. "Sometimes it works. Sometimes it doesn't. We'll find out."
Cubs manager David Ross tried to keep his clubhouse confident after Saturday's grueling game, which lasted four hours and 24 minutes.
"We have a resilient team," Ross told reporters. "A lot of fight from these guys tonight. We have small things to work on."
He will turn to successful rookie left-hander Jordan Wicks (3-0, 1.99 ERA) to try turn back the Diamondbacks.
Wicks will start against Arizona right-hander Ryne Nelson (7-8, 5.53 ERA).
Wicks will face the Diamondbacks for the first time.
"The thing that has stood out the most to me since he's gotten here is the ability to pitch with a lead," Ross said. "He's going to be on the attack. He's not worried about a baserunner. He'll still try to pitch his game, get ground balls for the defense and be efficient."
Nelson, in his second year in the majors, won his only start against the Cubs on Sept. 7 in Chicago on the same day he was called up from Triple-A Reno.
He allowed one run on two hits and two hits while striking out three in 5 2/3 innings in Arizona's 6-2 win.
—Field Level Media