Lohse smacked two RBI singles against Samardzija but saved his best work for the mound, where he struck out six, limited the Cubs to three singles and allowed only one runner past first base.
It was Lohse's eighth shutout and his second in two seasons with the Brewers.
"He sets a good example for what you need to do in a baseball game to get hitters out," catcher Jonathan Lucroy said. "And the best part about it is his stuff is not overwhelmingly nasty. He just locates, and he mixes. That's what it's all about, and that's what he does."
"Rarely do you see a game," right fielder Ryan Braun said, "where nine runs are scored and it's two hours and 20 minutes. It's a lot of fun on defense when a guy like that is pitching."
Lohse actually beat Braun's time by two minutes, shutting down a Cubs lineup without slugger Anthony Rizzo following his fourth-inning ejection in a tidy 2 hours, 18 minutes. The Cubs didn't have a hit until Junior Lake singled leading off the fourth, and Lohse worked around singles by Cubs reliever Brian Schlitter and right fielder Nate Schierholtz in the seventh.
Pitch count was never a problem for Lohse, who was even more efficient last year in an 89-pitch, two-hit shutout of the Braves. Against the Cubs, he threw only 27 pitches through three innings and never threw more than 15 pitches in a single frame.
"It was going smooth," Lohse said. "I was just getting the ball and throwing it. 'Luc' called a good game. When you're executing pitches, mixing it up, and they're swinging early in counts, it helps. … Obviously, you score some runs off Samardzija, it gets you in the game quick."
Lohse fed off the Cubs' aggressive approach, recording 17 of his 27 outs in at-bats of three or fewer pitches, including seven one-pitch outs.
"I mean, there's a lot of teams that try to swing early on me because they know I'm going to be pouring first-pitch strikes in, and a lot of times they foul them off," Lohse said. "You try to take advantage of it. You know what kind of guys you're facing. When you're out there staying out of the middle of the plate and making pitches and they're swinging at it, you're probably going to be successful more times than not, and that's the way it went today."
He was at 83 pitches entering the ninth inning.
"I didn't even go talk to him," Brewers manager Ron Roenicke said. "When you see that kind of game and the pitch count that low, it's impressive. These guys [the Cubs] swing the bats well against us. When he goes through guys like that, I know he's got it working."
Lohse has had it working more often than not since he signed a three-year contract with the Brewers last spring. He has easily been Milwaukee's most consistent pitcher over the past two seasons, now 18-11 with a 3.13 ERA in 44 Brewers starts.
"We were talking about it this morning -- if we hadn't signed him, where would we be?" Roenicke said.
Roenicke anticipated a pitchers' duel against Samardzija, who entered the day with a 1.68 ERA but saw it balloon to 2.54 in the shortest start of his career. Braun hit a two-run home run in the first inning off Samardzija's fourth pitch. The Brewers added a run in the second inning after a missed popup and five more runs in the third to break open the game.
Lohse hit run-scoring singles in the second and third innings, Gennett doubled in each of his at-bats against Samardzija and Lyle Overbay delivered a three-run double in the third inning as Milwaukee's lead grew to 8-0.
Gennett added a solo home run in the fifth inning off Cubs reliever Justin Grimm, Gennett's first homer since May 4.
"When you face a team that has a plan, you can definitely tell," Samardzija said. "They're not only feeling good but going up with a lineup plan. They jumped on my fastballs, and that was their plan today."
"What can we do?" Cubs catcher Welington Castillo said. "We cannot change the plan or whatever stuff he has. We can't pitch afraid. He's going to go right at him with the best stuff he has."
When a reporter said it was as if "the Brewers knew what was coming," Castillo responded: "That's what it looked like. [Samardzija] was throwing the ball like he always does. His 'velo' was there, breaking pitches were there. They were just on the pitches he threw."
The outburst marked a rebound for a Brewers offense that had been shut out by another Cubs right-hander, Jason Hammel, less than 24 hours earlier. Braun again led the way, connecting for a first-inning home run for the second time in the three-game series after hitting no homers in the Brewers' first 27 home games.
Was it a sign Braun was moving beyond his nagging rib cage strain?
"I hope so," Roenicke said. "I've seen better swings from him. We'll see, but I hope that's a real good sign."