Arenado hit a two-run homer in his first at-bat of the series on Friday to take a two-homer lead over Carter. But then Carter went deep in his next at-bat to lead off the fourth. Carter then went on to hit the decisive homer in the 10th inning of Saturday's game to tie Arenado at 41.
This comes one year after Arenado shared the NL homer title with Nationals right fielder Bryce Harper, who tied him at 42 on the second-to-last day of the season, the day after Arenado hit his final homer.
"I had a two-homer lead after the first at-bat of the series, but he hits homers, he can hit, you've got to give him credit, he tied me up," Arenado said. "But it's cool to lead in anything. It's unbelievable, and I'm very thankful. I know it would be cool to win by myself, but at the same time, he's had a great year for himself. I'm just happy that I had another good year. It's a cool thing to be a part of, being up there at No. 1."
Arenado, 25, has been an All-Star for two seasons in a row, but Carter's season has been a bit of a surprise. He's always had big power -- his .245 isolated power from 2012 to 2015 ranks eighth among qualified hitters -- but he had only eclipsed 30 home runs once before.
Non-tendered by the Astros, the Brewers signed Carter for $2.5 million this offseason with $500,000 in incentives, all of which he reached. He was rookie general manager David Stearns' only Major League free-agent acquisition and paid off handsomely.
"I'm still happy, ending up having the season that I did," Carter said. "Getting to 40, especially bouncing back after being non-tendered, and being consistent like I was able to be this year."
But now for the important question: Will they saw a home run trophy in half for the duo?
"I don't know, you'll have to ask [Arenado]," Carter said. "He went through this last year, too."
Ben Weinrib is a reporter for MLB.com based in Denver.
Adam McCalvy has covered the Brewers for MLB.com since 2001. Follow him on Twitter @AdamMcCalvy, like him on Facebook and listen to his podcast.
This story was not subject to the approval of Major League Baseball or its clubs.