Phoenix, AZ -- (Sports Network) - Stephen Drew, Conor Jackson and Adam Dunn each knocked in two runs en route to helping the Arizona Diamondbacks extend their lead in the NL West with an 9-3 win over the suddenly struggling Los Angeles Dodgers.

"It is always nice to get another game but we have to play better," Diamondbacks manager Bob Melvin said. "If we played better in the San Diego series we would be looking at a couple more games. It is nice to get the first game of the series but we still have two left and we need to get at least one more of these."

Doug Davis (6-8) hurled the minimum five innings to earn the win, scattering eight hits, three walks and two runs for Arizona, which moved 4 1/2 games into top spot in the West by winning the opener of this critical three-game set and snapping a four-game slide.

"Tonight I was able to make my pitches and get the key out," Davis said. "But you have to give credit to the guys who scored three (runs) after I gave up a couple."

Hiroki Kuroda (7-10) was credited with the loss after allowing four runs -- just two earned -- on four hits in five innings of work. Manny Ramirez was 4- for-4 with two doubles, two runs scored and a walk, but it wasn't enough as LA lost its season-high eighth straight affair.

"Right now it is not even matter of who we play, although we understand who we are playing and what the importance is," Dodgers manager Joe Torre said. "We are struggling. We need to really find a way to get this stuff straightened out. There is still plenty of time left. Right now the last couple of weeks have been ugly and that has to change."

After LA took a 2-1 lead in the top of the fifth, Arizona struck with three in the bottom half. With two runners on, Augie Ojeda reached base on Nomar Garciaparra's throwing error, and Chad Tracy came in to score on the mishap.

Jeff Salazar then hit a pinch-hit RBI single up the middle and Drew lofted a ball deep enough to left to let Ojeda cruise home for a 4-2 lead.

Blake DeWitt's pinch-hit single in the seventh brought home Ramirez, but Arizona's subsequent four-run inning allowed the home team to run away with the win.

Chan Ho Park, who recorded the last out of the sixth, surrendered three straight hits, including an RBI single to Drew, before another Garciaparra error scored Drew to make it a 6-3 game.

Joe Beimel came on in relief and was greeted by consecutive RBI singles from Dunn and Mark Reynolds before recording the final three outs of the inning.

Jackson doubled in Tony Clark in the home eighth for good measure.

The NL West leaders broke a scoreless tie in the fourth when Dunn roped a two- out, opposite-field double down the left-field line, scoring Chris Young from first.

The Dodgers wasted a bases-loaded opportunity in their first at-bat, but filled the bags again in the fifth before getting a pair of runs on Matt Kemp's sacrifice fly to center and James Loney's single up the middle.

Game Notes

The last time the Dodgers lost eight in a row was July 19-26, 2006. LA has dropped 10 straight on the road, the longest streak as a visitor since losing 11 straight back in 1991..Diamondbacks manager Bob Melvin was ejected in between the fifth inning and sixth inning for arguing a fan interference call...The D'Backs were busy making moves before the game, claiming pitcher Wilfredo Ledezma off waivers from the San Diego Padres, activating Justin Upton from the 15-day disabled list and recalling pitcher Max Scherzer from Triple-A Tucson. Upton hit a pinch-hit double and Scherzer worked a scoreless inning of relief. To make room on the roster, the D'Backs optioned outfielder Alex Romero and pitcher Leo Rosales to Tucson...LA also made a move before the game, optioning pitcher Clayton Kershaw to Triple-A Las Vegas and purchasing the contract of pitcher Scott Elbert from Double-A Jacksonville. Elbert made his Major League debut in the sixth inning, going 2/3 of an inning with a walk and two strikeouts...Dodgers second baseman Jeff Kent left the game in the sixth inning with left knee pain.