PHOENIX — Wade Miley struggled in his last start against San Francisco, digging his hole deeper as he tried to power his way out of it.
With some advice from his coaches, the Arizona left-hander worked on slowing things down between starts.
It turned out well in a rematch against San Francisco, putting a dent in the Giants' NL West chances.
Miley pitched seven effective innings, Mark Trumbo hit a grand slam and had five RBIs, and the Diamondback sent the Giants to the third straight loss, 6-2 on Monday night.
"He was frustrated and throwing hard, yanking a lot of balls, unable to make an adjustment," Diamondbacks manager Kirk Gibson said of Miley's previous start. "Today he got out there and slowed down and got into a rhythm really nice."
A pair of losses to the Dodgers over the weekend hurt San Francisco's NL West chances, but Giants were still in control of the NL wild card, entering Monday's game three games up on Pittsburgh for the top spot.
What the Giants couldn't afford was a letdown in a three-game series at Chase Field, where they had won 16 of 22 games and six straight series since 2012.
The start of this series against the struggling Diamondbacks didn't go so well.
Miley (8-11) bounced back from his shortest outing of the season by slowing down his mechanics, allowing one run.
Trumbo started Arizona's homestand strong and kept it going against the Giants, hitting his ninth homer off Vogelsong (8-11) in the third inning and a run-scoring single off Juan Gutierrez in the seventh. Trumbo has six hits and nine RBIs the past three games.
"They scored all three runs with two outs," Giants manager Bruce Bochy said. "We had a couple of pretty good opportunities, but couldn't get it close enough to put a little more pressure on them.
Vogelsong pitched 6 2-3 scoreless innings against the Diamondbacks his last outing, but was in trouble by the third in his 30th start of the season. The Diamondbacks loaded the bases against him and Trumbo cashed in, ending a 120 at-bat homerless streak by lifting his second career grand slam just over the wall in right.
Arizona loaded the bases again in the sixth against Vogelsong, but Javier Lopez ended the threat by inducing a groundout on his first pitch.
Vogelsong allowed four runs and six hits with four walks and five strikeouts.
It was a bad inning; it wasn't very good," Vogelsong said.
Miley had his shortest outing of the season his last start against the Giants, lasting just two innings after giving up three runs and five hits.
He was much better against the Giants in his 100th career start, escaping a jam in the second inning and giving up one run on Brandon Crawford's groundout in the seventh.
"You've just got to put those behind you — those (games) are going to happen," said Miley, who struck out four. "You've just got to make adjustments and go on to the next one."
Giants OF Angel Pagan tried to play Monday night despite a stiff back. When his back was still tight during batting practice, the Giants pulled him from the lineup, hoping that he'd be able to play Tuesday after receiving treatment.
"We miss him when he is not in the lineup," Bochy said. "We are a different club. He is our leadoff hitter, our catalyst. He is the guy that kind of makes things go.
The Giants had been on a tear with runners in scoring position, hitting .361 over the past 18 games. They couldn't come through against Arizona, going 2 for 10 while stranding nine runners.
Giants: 1B Brandon Belt was activated before the game after clearing concussion protocols. He had been on the DL since Aug. 8.
Diamondbacks: OF David Peralta (back) has resumed all baseball activities and could join Arizona for its final road trip.
Giants: RHP Jake Peavy, Tuesday's starter against Arizona, has allowed two earned runs or less in six straight starts. He pitched 5 2-3 innings of one-run ball in a 6-2 victory over Arizona on Thursday.
Diamondbacks: RHP Josh Collmenter is 2-0 with a 0.65 ERA over his last four starts, leaving him one win shy of matching his career high of 10.