The win gave the Reds a three-game sweep over their cross-state rivals.
Phillips, Zack Cozart and Ryan Ludwick each had three hits and 10 different Cincinnati players scored runs Thursday.
The Indians staked starter Josh Tomlin (3-4) to a 2-0 run in the first on a Shin-Soo Choo, who had two home runs, leadoff homer and a run-scoring groundball but Tomlin failed to hold the lead. Cincinnati lit Tomlin up for 10 hits and six runs in four innings.
The first three Reds batters had hits, with Votto making the score 3-2 with his 12th home run of the season. Phillips, who matched his three-hit, one home run game from Wednesday, hit a solo home run in the third.
Phillips singled in two runs in the fourth and, after Choo's second homer, Cincinnati scored five times in the fifth, with a two-run home run by Ludwick the big hit in the rally, for an 11-3 lead.
Kristopher Negron scored for the Reds in the sixth on a wild pitch but Cleveland wrapped up the scoring with a pair of runs in the seventh.