Kent's towering shot to left on a 3-2 pitch from Luis Vizcaino (3-4) put the Dodgers back on top after Arizona had rallied from a 3-1 deficit to tie it. Jonathan Broxton (3-0) threw one pitch, a line out by Johnny Estrada to end the eighth, to get the victory.
Takashi Saito, who blew his second save in 15 tries in Friday night's 9-7, 15-inning Arizona victory, pitched a scoreless ninth for his 15th save.
Los Angeles remained one game ahead of second-place San Diego in the NL West. The Padres won at Colorado. Arizona fell four games back with its fifth loss in six games.
Dodgers starter Derek Lowe lasted only 3 2/3 innings before leaving with a bruised left thumb. Lowe, winner of four of his last five starts, was struck in the left hand by Chad Tracy's line drive. X-rays were negative.
Lowe allowed a run on five hits, three of them infield singles.
With Arizona's bullpen spent from Friday night's marathon, Miguel Batista went eight innings, allowing three runs on only four hits but getting no decision. He blanked Los Angeles without a hit the last four innings.
Orlando Hudson, who hit the game-winning homer Friday night, was 3-for-4 for including an RBI single to tie it at 3-3 in the eighth.
Nomar Garciaparra's two-out single past diving first baseman Tony Clark brought in two runs in the third.
The Dodgers added a run in the fourth when Andre Ethier doubled off the Arizona bullpen fence in left, then scored from third when shortstop Craig Counsell fielded Lowe's grounder for what should have been a routine inning-ending out. But Counsell chose to toss it to second for the force out, and Hudson didn't get to the bag on time.
Hudson led off the Arizona fourth with a double, then committed a pair of base-running blunders. First, he failed to tag up and take third on Luis Gonzalez's fly out to deep center, then he was thrown out trying to steal.
Lefty Joe Beimel relieved the injured Lowe and gave up consecutive singles to Estrada and Clark. Clark's grounder up the middle brought Tracy home from second to cut the lead to 3-1.
The Diamondbacks made it 3-2 in the seventh. Estrada led off with a double down the right-field line, took third on Clark's fly out to deep right, then scored on Counsell's sacrifice fly to center.
Just as they did Friday night, the Diamondbacks tied it in the eighth. Stephen Drew led off with a pinch-hit single off Brett Tomko, was sacrificed to second by Eric Byrnes' bunt, then scored on Hudson's single up the middle.
The crowd of 40,358 was Arizona's largest at home this season. ... Counsell got his first start since coming off the disabled list.