PHOENIX -- Jake Lamb hit his second career grand slam, his first off a left-hander, in the seventh inning and the Arizona Diamondbacks rallied to beat Los Angeles 6-3 on Tuesday night, only the eighth loss for the Dodgers in their last 52 games.
Lamb, who also had a solo home run in the sixth inning, was hitting .143 against left-handed pitchers this season when he hit Tony Watson's 1-2 pitch off the right field foul pole to put Arizona up 6-3.
Justin Turner homered twice for the Dodgers, who led 3-2 entering the bottom of the seventh. Chris Iannetta had a solo home run for the Diamondbacks.
The Dodgers lost for just the fourth time in 29 games since July 4.
Closer Fernando Rodney, who blew a three-run lead in a 5-4 loss at the Dodgers on July 6, threw a scoreless ninth for his 26th save in 31 tries.
David Hernandez (2-0) got the final out in seventh inning to get the victory.
Iannetta led off the seventh with a single off Brandon Morrow and Kenta Maeda struck out.
With left-handed batting Chris Herrmann announced as a pinch hitter, Dodgers manager Dave Roberts brought in the lefty Watson, leading Arizona's Torey Lovullo to replace Herrmann with righty Adam Rosales.
Rosales was hit by a pitch and, with two outs, A.J. Pollock was walked intentionally to load the bases and bring up Lamb against Watson, a former closer acquired in a trade deadline deal with Pittsburgh.
Both of Turner's home runs came off Zack Godley, one in the fourth inning, the other in the sixth.
Maeda had his string of four straight victories come to an end. He went five innings, allowing one run and four hits with six strikeouts and one walk.
Pedro Baez relieved Maeda in the sixth and promptly gave up an opposite-field home run to Lamb to cut the lead to 3-2.
Yasiel Puig robbed J.D. Martinez of what would have been a game-tying home run with a soaring grab above the right field fence in the sixth inning.
Umpire Joe West was to have worked the Dodgers-Diamondbacks series but was suspended for three games for comments he made about Texas third baseman Adrian Beltre.
Dodgers: LHP Clayton Kershaw (back) threw aggressively from flat ground before the game and Roberts said he expects the left-handed ace to throw a bullpen session when the team returns to Los Angeles to face San Diego over the weekend. … C Austin Barnes was out of the lineup after taking a foul ball off his throwing hand Sunday against the New York Mets. X-rays were negative and Roberts said he could be back in the lineup on Wednesday.
Diamondbacks: LHP Robbie Ray, in the concussion protocol, threw 28 pitches in a bullpen session on Monday and played catch on Tuesday. Lovullo said Anthony Banda would make Ray's scheduled start against the Dodgers on Thursday.
In a matchup of two of the NL's most successful pitchers, RHP Rich Hill (13-1, 2.33 ERA) goes for the Dodgers and RHP ace Zack Greinke (13-4, 3.10) for the Diamondbacks in the second game of the three-game series.