PHOENIX -- It has not taken San Diego Padres manager Pat Murphy long to know what he has in James Shields.

"He's a winner," Murphy said.

For the time this season Friday, that did not translate on the mound.

Arizona right-hander Rubby De La Rosa outpitched Shields in the Diamondbacks' 4-2 victory over the Padres at Chase Field, giving up only five hits and two runs (one earned) in seven-plus innings.

Shields (7-1) gave up eight hits, four doubles, and four runs in six innings. He was victimized by a three-run Arizona third inning, when the D-backs built their lead to 4-0 with four hits and a walk.

"It was a grind day," said Shields, who lost his first regular-season game since Sept. 20, 2014, while with Kansas City.

"Right out of the gates. Sometimes you don't have your best stuff. There are a lot of times you have to pitch without your best stuff."

De La Rosa (6-3) struck out six and walked three to win for the fourth time in five decisions as Diamondbacks (33-34) won for the sixth time in eight games.

Arizona center fielder A.J. Pollock had two hits and scored a run, shortstop Nick Ahmed had two hits and an RBI and first baseman Paul Goldschmidt singled and walked. Goldschmidt leads the majors with a .358 batting average.

Pollock doubled off the left-field fence on the first pitch Shields threw in the game, scoring on a Goldschmidt groundout.

Left fielder David Peralta, second baseman Aaron Hill and catcher Welington Castillo doubled in the three-run third inning, and Ahmed capped the inning with an RBI single to center on a nine-pitch about to make it 4-0.

"It wasn't his best outing, but he's a fighter," Murphy said of Shields. "We could have done some things to help him a little bit more, but I always feel great when you have a winner out on the mound."

Arizona right-hander Brad Zielger pitched around a walk and left fielder Justin Upton's two-out double in the ninth inning for his 10th save in his 500th career appearance.

Shields scored San Diego's first run after a two-out single in the fifth inning. Third baseman Yangervis Solarte singled and first baseman Yonder Alonso walked before De La Rosa walked Upton to force in a run. De La Rosa struck out right fielder Matt Kemp to end the inning.

Second baseman Cory Spangenberg singled and had a sacrifice fly after two Arizona infield errors in the eighth inning for San Diego (33-37), which is 1-3 under Murphy and has lost five of its last six.

Shields gave up five runs and four homers in a 6-5 victory at Chase Field on May 8.

De La Rosa has won his last two starts, both with Castillo behind the plate. De La Rosa went eight scoreless innings in a 4-0 victory at San Francisco on Sunday.

"He did another great job," Arizona manager Chip Hale said.

NOTES: San Diego purchased the contract of 1B/3B Brett Wallace from Triple-A El Paso on Friday and optioned RHP Cory Mazzoni to El Paso. Wallace, who played for new Padres interim manager Pat Murphy at Arizona State, was hitting .298 with eight homers and 37 RBIs in 60 games at El Paso. He rounded out as a pinch-hitter in the eighth. LHP Eury De La Rosa was designated for assignment to make room on the 40-man roster. ... San Diego RHP James Shields made his 300th career start Friday, his 301st career appearance. ... Arizona RHP Archie Bradley (shoulder tendinitis) threw 54 pitches in a simulated game Thursday, and manager CHip Hale said he will wait to see how Bradley recovers being determining the next step. ... Murphy, who spent 15 seasons as the baseball coach at Arizona State, said he has received 1,400 text messages since taking the job. Among them: former ASU players Jason Kipnis, Ike Davis, Mike Leake and Kole Calhoun. ... Former ASU infielder and current Oakland 2B Eric Sogard beat the Padres with a ninth-inning single in Murphy's first game Tuesday. His text to Murphy: "I'm sorry."