Arenado's Statcast-projected 424-foot shot in the second was key for the Rockies, as it gave them the lead after the Cardinals tied the game in the top of the inning.
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"It felt good," Arenado said. "You walk [Carlos Gonzalez] on four pitches, and I was just ready to hit. I was like, 'First pitch, he might throw a fastball to try to get ahead here.' I was just ready to hit. He threw it middle-in, and I just put a good swing on it. I think he missed his spot, and I was able to take advantage of it."
Those four RBIs bring Arenado's season total to 128, which leads the Majors. Last season he led the National League with 130 RBIs -- 20 more than second-place Paul Goldschmidt drove in -- yet Arenado was eighth in NL MVP voting with no first- or second-place votes.
"At the end of the day, it feels like the MVP every year is on a winning team," said Arenado, whose Rockies finished last in their division at 68-94. "You've got to win ballgames, I feel like, to get that trophy, unless you have a spectacular year like Bryce Harper last year, which is a unique year. I'm just happy I'm staying consistent.
"My thing is after last year, a lot of people were questioning if I could do it again. I'm happy I'm able to put those questions to rest by having another good year. I'm just focused on helping the team win, and good things are happening."
Arenado is three homers shy of his career high of 42 with 10 games to go, but he already set a career high with 111 runs, and his .294 average is seven points higher than his previous best.
"The home runs would be great to eclipse, but that's hard to do, so I'm not too worried about the home runs, but the RBIs is something I really want to beat," Arenado said. "I know I'm pretty close, but either way, it's hard. Whatever I do the rest of the year, I'll be happy. I definitely want to drive in more runs."