Ellis' bases-loaded shot in the top of the eighth inning handed the Dodgers a 10-0 lead following a six-run third, highlighted by a two-run shot from Hanley Ramirez.
The Dodgers' bullpen collapsed in the bottom of the eighth, when the Rockies sent 11 men to the plate and scored seven runs on six hits.
Ronald Belisario put out the fire, recording the final five outs to collect his first save, as Los Angeles snapped a three-game losing streak.
Adrian Gonzalez added two hits and a pair of RBI while starter Joe Blanton (9-12) earned his first win as a Dodger after three losses since being acquired from Philadelphia. Blanton allowed three runs on 10 hits over 7 1/3 frames.
Second-place Los Angeles came into the contest trailing National League West-leading San Francisco by 3 1/2 games.
Drew Pomerenz (1-8) was tagged for six runs (five earned) on six in a four-inning effort for Colorado.