CHICAGO -- The Chicago Cubs played more like the reigning World Series champions on Tuesday.
Cubs manager Joe Maddon said it was a matter of time before Chicago solved Brewers starter Jimmy Nelson.
"I didn't think Nelson was as sharp as we had seen him, and I was looking at him more than our guys," Maddon said. "Guys that were having bad at-bats against him in Milwaukee were having good at-bats against him tonight. So, I thought we were going to score some runs."
Although Chicago starter Brett Anderson struggled in a 3 2/3-inning outing, there were plenty of highlights for the Cubs, including the effort of five relievers who collectively allowed just one run on two hits in 5 1/3 innings.
"We're going to be fine out there, it's all about confidence," said Maddon. "We've just got to them out there. As they get more successful innings -- which they shall -- their confidence will come on because they're really good."
Chicago rallied from a 7-4 deficit with a four-run sixth keyed by Albert Almora's two-run pinch single and Jon Jay's RBI triple.
The comeback overshadowed another big night for the Brewers' offense. Eric Thames went 3-for-5 with three runs to extend his hitting streak to 12 straight starts. Travis Shaw was 3-for-4 with a homer, three RBIs and two runs.
Almora singled home Montero and Javier Baez with one out to trim the Milwaukee lead to 7-6 and chase Nelson.
Reliever Jared Hughes gave up the triple to Jay that drove in Almora to make it 7-7. A two-out wild pitch brought home Jay for an 8-7 Cubs lead.
Nelson worked 5 1/3 innings, allowing seven runs on nine hits. He walked one, struck out three and gave up two home runs.
"That's usually a pretty aggressive team," said Nelson, now 1-7 all-time against Chicago. "They know what they want, their zone, their pitch. They do a good job of not missing it."
Hughes (1-1) allowed two hits and a run in two-thirds of an inning.
Cubs reliever Justin Grimm (1-0) worked a scoreless sixth inning for the win, and Carl Edwards and Hector Rondon followed with one shutout inning apiece. Right-hander Wade Davis pitched a 1-2-3 ninth for his third save.
Anderson allowed six runs and eight hits.
The Brewers jumped to a first inning lead for the second straight night.
Thames lined a one-out double into the right field corner off Anderson and reached third as Ryan Braun followed with a single to right.
Shaw's double to left brought home Thames for a 1-0 edge while Domingo Santana sent a liner off Anderson's leg as Braun came home for a 2-0 lead. Anderson recovered to throw out Santana at first.
Manny Pina made it 3-0 as he launched a 1-0 pitch into the left field corner for a double to score Shaw.
Thames and Braun reached again in the third -- on a double and infield single, respectively -- and Shaw drove in Thames for a 4-0 lead with none out with a double to center. Santana's sacrifice fly to right scored Braun to make it 5-0.
"The middle of our lineup is carrying our offense right now, there's no question," said Brewers manager Craig Counsell. "Braun and Thames are doing a heck of a job and Travis Shaw had a nice job tonight. (But) we've got to get some contributions down at the bottom,
The Cubs got two runs back in the third when Jay walked and leadoff batter Schwarber launched a two-run homer -- his third of the season -- to right.
Orlando Arcia's first home run of the season led off the fourth for a 6-2 Milwaukee lead.
Maddon pulled Anderson with two out in the inning and just before Thames came up for his third plate appearance. Left-handed reliever Brian Duensing gave up a single to left for Thames' third hit but struck out Braun to close the inning.
Montero's fourth inning homer to right scored Jason Heyward and cut the deficit to 6-4, but Shaw replied in the fifth with a solo homer -- his third of the season -- to make it 7-4.
NOTES: Brewers SS Orlando Arcia has gone 37 consecutive games without committing an error dating back to Sept. 5, 2016, against the Cubs. His fourth inning leadoff homer was Milwaukee's major-league-leading 26th long ball of the season, and 3B Travis Shaw added No. 27. ... Following Wednesday's series finale, the Brewers return to Miller Park to begin a 10-game homestead opening Thursday with the first of four games against St. Louis. ... Brewers LHP Tommy Milone (1-0, 7.36 ERA) will go against Cubs RHP Kyle Hendricks (1-1, 5.73 ERA) in the series finale Wednesday afternoon. ... It was a night of more awards for Cubs players as 1B Anthony Rizzo and OF Jason Heyward received 2016 Gold Gloves prior to the game. ... LF Kyle Schwarber grounded out to open the Cubs' first Tuesday, but he has reached base in 7 of 14 leadoff plate appearances this season.