Arenado hit a three-run homer during a seven-run burst in the first inning, then added another three-run drive in the fourth. He leads the majors with 104 RBIs — he had a big league-high 130 last year — and tops the NL with 32 home runs.
Arenado was 1 of 16 on the Rockies' homestand before getting four hits. He passed Cubs slugger for the NL homer lead.
Jorge De La Rosa (8-7) tossed eight innings, giving up a pair of home runs to Addison Russell.
De La Rosa delivered a two-run single in the first as the Rockies quickly ended Jason Hammel's 22-inning scoreless streak.
