Corey Seager was in the middle of everything with four hits, including his first major league home run, and three RBI in the win, which lowered the Dodgers' magic number to clinch the National League West down to 14.
Carl Crawford homered to open the game in the first inning, the Dodgers' third leadoff home run in their last four games, by three different players. Later in the inning, Seager beat out an infield single to bring home a second run.
Seager added an RBI single in the third inning, an inning that saw the Dodgers score five runs, including two more home runs, the first of which was hit against De La Rosa by Adrian Gonzalez. De La Rosa only faced four batters in the third inning, and all of them scored.
De La Rosa has had a terrible time against his old team, allowing 22 runs on 28 hits in 17⅔ innings, an 11.21 ERA, including seven home runs, five walks and 18 strikeouts.
In the fifth inning Seager came to the plate having reached base in six consecutive plate appearances, with three singles and three walks to that point. The streak looked like it might come to an end when Seager lofted a pop fly down the left field line against Josh Collmenter.
Left fielder David Peralta had a beat on the ball, but it was caught by a fan wearing Diamondbacks gear who reached into the field of play to make the catch.
Here is a picture of the Dbacks fan who reached out to take the out from his team. Seager went yard on the next pitch pic.twitter.com/7ONEnm26JY— Ryan Walton (@RyanWaltonMLB) September 13, 2015
Seager could have been called out for fan interference, but wasn't, which was a good thing for the Dodgers because he launched a ball well into the right field seats for his first major league home run.
He then walked in the seventh inning and doubled in the ninth, Seager's ninth straight plate appearance reaching base.
Through his first nine major league games, Seager has at least one hit in all eight starts and is hitting .467/.568/.733 with five doubles, a home run, two stolen bases, seven walks, eight runs and seven RBI in 37 plate appearances.
Bolsinger goes short
Staked to a 7-0 lead after three innings, Mike Bolsinger did not last long enough to qualify for the win. Arizona threatened against Bolsinger in each of the first four innings, finally breaking through with three runs in the fourth.
After Bolsinger allowed seven hits and four walks, he was lifted after 3⅔ innings and 80 pitches. It could have been even worse for Bolsinger, who left with the bases loaded, but J.P. Howell got Peralta to fly out to short left.
Earlier than usual
Howell made one pitch in the game and was awarded the win, by official scorer's discretion since Bolsinger didn't complete five but left with a lead that was never relinquished. Howell's one-pitch win was the second by a Dodgers pitcher this year (Chris Hatcher had the other one, on May 22).
Two outs in the fourth inning was also the earliest Howell entered a game since pitching part of the second inning of a Sept. 14, 2013 game, a forgettable 19-3 loss to San Francisco.
It was Crawford who ran a fair distance to catch that rally-ending fly ball to end the fourth inning, and in the fifth inning he was pinch hit for by Scott Schebler.
Crawford left the game with tightness in his right hamstring, and is day-to-day per the team. With a left-handed pitcher starting on Sunday for Arizona, Crawford wasn't likely to start anyway.
Not only rookie star
Seager wasn't alone among rookie contributors on Saturday, as Joc Pederson joined the home run brigade with a third-inning shot against Andrew Chafin, a two-run shot that put the Dodgers up 7-0. It was Pederson's fifth home run in 105 plate appearances against southpaw pitchers this season.
It was also the 25th home run of the season for Pederson, tying Del Bissonette (1928) for second-most by a Dodgers rookie. The gold standard remains Mike Piazza, with 35 home runs in 1993.
Pederson also had two singles on the night and in September is hitting .313/.436/.531 in nine games.
Alex Guerrero hit a pinch RBI double in the ninth inning, his first extra-base hit since July 31, snapping a string of 32 plate appearances without.
Andre Ethier added two hits, including his 299th career double.
The Dodgers go for the series win on Sunday afternoon, with Zack Greinke on the mound against left-hander Patrick Corbin for the Diamondbacks.
Home runs: Carl Crawford (4), Adrian Gonzalez (27), Joc Pederson (25), Corey Seager (1); David Peralta (15)
WP - J.P. Howell (6-1): 1 up, 1 down
LP - Rubby De La Rosa (12-8): 2+ IP, 9 hits, 6 runs, 1 strikeout