Rather than intentionally walk the dangerous Sosa, the Diamondbacks decided to pitch to him because of Kim's success against the slugger.
Sosa swung and missed at a 1-2 pitch, leaving him 0-for-9 with seven strikeouts lifetime against Kim.
Kim got his 32nd save.
The Diamondbacks' last loss before starting their current four-game win streak was Aug. 18 at Chicago.
Todd Hundley had a two-run homer for the Cubs.
Wood (9-7) struck out 12 and gave up just three hits, but remained winless in August. He's 0-2 in five starts this month.
Wood got in trouble in the eighth, walking pinch-hitter Quinton McCracken, who reached second on a sacrifice by Alex Cintron.
That brought up Womack, who had a two-run, game-winning homer Thursday night against Cincinnati. Womack pulled a pitch to deep right field, and McCracken scored easily on the double.
Helling (9-8) allowed two runs, eight hits and two walks in seven innings.
Alex Gonzalez, whose 15-game hitting streak ended Thursday night at Houston, led off the Cubs fifth with a triple. Hundley followed with his 13th home run to tie it at 2.
In the first, Wood got two out before Junior Spivey turned on a 97 mph fastball and pulled it into left field for a single.
Then Luis Gonzalez hit an opposite-field drive that curled into the lower grandstand in left.
It was the 25th homer for Gonzalez, who returned to the lineup Thursday after sitting out seven games because of a ribcage injury.
Notes: Hundley, a switch-hitter, has 12 homers from the left side. ... The crowd of 47,095 was the 14th sellout in Phoenix, home to thousands of Midwest transplants. ... The Cubs called up RHP Alan Benes, a non-roster invitee to spring training, from Triple-A Iowa before the game. ... Jay Bell was the 16th batter hit by Wood this year, the most by a Cubs pitcher since Ed Reulbach hit 18 in 1905.