"If things are going bad, I feel like I can be a guy that can right the ship with one good start," Arrieta said. "A lot of the guys here fall into that category."
Chicago, assured of its fourth straight losing season, had dropped seven of eight coming in after opening its trip with consecutive wins in Cincinnati.
Cubs manager Dale Sveum was pleased with Arrieta's eight starts since he was acquired from Baltimore on July 2.
"Everything was working really well," Sveum said. "He hung that one cutter to Gomez, but other than that, a lot of weak contact."
Arrieta allowed three hits, struck out five, walked one and drove in a run.
"It was pretty much just good control from start to finish," he said. "I established a good, quality fastball and worked offspeed off of that. We had a nice roll going today."
Valbuena stopped an 0-for-14 slide with his 12th homer, a solo shot off Kyle Lohse (10-10) in the first. Schierholtz hit a two-run homer in third that landed in the Cubs bullpen in center for a 3-0 lead, and Bogusevic added a pinch- homer off Donovan Hand leading off the ninth.
Lohse gave up three runs and seven hits in five innings. He has allowed 26 homers, tying Washington's Dan Haren for the NL lead.
Lohse and the Brewers weren't happy with home plate umpire Chad Fairchild.
"Not a whole lot of it was me," Lohse said. "When you have an umpire that says your grumpy face is going to cost you strikes, you've got issues. I wasn't as consistent as I want to be, but I made a lot of really good pitches and I guess I looked funny out there and wasn't going to get the calls."
Lohse said wasn't told of Fairchild's comment after until he finished the fifth inning.
"Luckily, they didn't tell me until later," Lohse said. "I don't think I did anything to show him up. I had a lot of calls that I thought could have went my way. Obviously, it is frustrating, but my job is to go out there and make pitches. I can't do anything about what is called or not, but it's just hard to adjust to something that's inconsistent."
Sixty-five of Arrieta's 86 pitches were strikes, while Lohse had 62 among 100 pitches.
Lohse said teammate Martin Maldonado passed on the comment, but Lohse didn't specify whether Maldonado told him directly.
"I didn't hear it firsthand or I wouldn't have lasted five innings," Lohse said.
Logan Schafer was cited for throwing equipment after he made the last out of the game. He tossed his helmet while walking away from Fairchild after taking a called third strike.
Cubs C Wellington Castro Brewers SS left after the seventh inning with right knee soreness. "I was running hard and I just felt a sharp pain," he said. Cubs manager Dale Sveum that Wellington would get checked on and evaluated tomorrow. ... Brewers SS Jean Segura did not play, a day after straining his right hamstring. ... Injured Brewers 1B Corey Hart, eligible for free agency after the World Series, wants to remain with the Brewers. He is making $10 million this year, the final season of a $26.5 million, three-year deal. "I wouldn't sit there and ask for anything that is outlandish," he said. "I would take a discount to stay here because I think I owe it to them to stay here and be a cheaper player." He had surgery on his right knee in late January and missed spring training. "I've told them I would be very generous to stay here. Nobody wants to play for free, but I've basically sat there and watched all season. That's kind of what we're hoping for, but at the same time, you don't know what's going to happen." ... Schierholtz's 21 home runs are 12 more than his previous high of nine with San Francisco in 2011.