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Arizona's Wade Miley was cruising along when one pitch changed his entire outing.

Jesus Guzman hit a two-run pinch-hit homer off Miley in the eighth that ignited a six-run inning that gave the San Diego Padres a 7-1 win over the Diamondbacks on Friday night.

Miley (6-2) had dominated the Padres through the first seven innings, allowing just three hits in a 1-1 game. He had yet to walk a batter before the game changed in a hurry.

"Miley's pretty good," San Diego manager Bud Black said. "You could tell by the way he was throwing the ball, he was going to be a tough test."

The rookie left-hander was in control before Alexi Amarista reached on a one-out bunt single. Guzman's shot on a hanging changeup started the offensive onslaught as San Diego sent 11 batters to the plate in the eighth against three pitchers.

Guzman's homer into the left-field stands helped the Padres snap a six-game losing streak

""I thought a changeup was a good pitch," Miley said. "I left it up a little bit and he capitalized. He's a good hitter."

Said Diamondbacks manager Kirk Gibson: "He just made one mistake. Give him (Miley) credit. The bunt to get on base. Now, you have a situation. He hung a (changeup).

"After that it was disappointing."

Chris Denorfia singled after Guzman's homer and David Hernandez replaced Miley. Denorfia scored on Cameron Maybin's triple. After a walk to Yonder Alonso, Carlos Quentin singled in a run.

The Padres loaded the bases and scored two runs on Nick Hundley's sacrifice fly and an error.

Miley allowed four runs and six hits in 7 1-3 innings with four strikeouts and no walks as his three-game winning streak was stopped.

"I thought I located well," Miley said. "Just that one pitch that got away."

Andrew Cashner (3-3) pitched the eighth for San Diego, which was coming off a 1-9 road trip. The Padres have worst record in the majors at 18-35.

The Diamondbacks went just 1 for 8 with runners in scoring position.

Arizona got on the board in the third inning on Miguel Montero's RBI single that scored Aaron Hill.

San Diego evened the score at 1-all in the bottom of the inning after Amarista lined a one-out triple into the left-field corner and scored on pitcher Clayton Richard's ground out.

Richard allowed one run and seven hits in 6 2-3 innings. The lefty struck out three and walked one.

The benches and bullpens emptied briefly in the eighth inning after Chris Young drew a two-out walk off Cashner.

Young apparently looked toward Cashner after he reached first base. The two started walking toward each other and the benches and bullpens emptied for about 30 seconds before the umpires directed both teams off the field.

"(Cashner) asked me what I was looking at," Young said. "I was trying to pick up signs from Matty (third base coach Matt Williams)."

Young attempted to steal second base and was thrown out by Hundley.

Notes: Diamondbacks 1B Paul Goldschmidt extended his career-best hitting streak to 10 games. ... Miley reached safely on an infield single in the seventh to extend his hitting streak to eight games and set a club record for a pitcher. ... Maybin returned to the starting lineup for the first time since Saturday when he sprained his right wrist. ... Arizona LF Jason Kubel returned on Friday after being placed on the paternity leave list Wednesday. ... Padres closer Huston Street began a rehab assignment Friday with Single-A Lake Elsinore. ... Arizona RHP Daniel Hudson (1-1, 5.48) will face San Diego RHP Edinson Volquez (2-5, 3.46) on Saturday night