PHOENIX -- Jeremy Hellickson gave up a leadoff homer, walked the next two batters and threw a ball into center field for an error.
The right-hander's return from the disabled list could not have gone much worse.
Hellickson barely made it out of the first inning and was done after that, giving up five runs in the Arizona Diamondbacks' 10-3 loss to the San Diego Padres Monday night.
"I feel that I haven't been on the mound my whole life," said Hellickson, who allowed a run in 13 1-3 innings before going on the disabled list. "It felt really weird out there. I've got to make an adjustment early and try to keep us in the game. Putting up a five spot before we even get a chance to bat is by far my worse inning of my career."
Wil Myers hit a leadoff homer in San Diego's five-run first inning off Hellickson (9-9) and added a three-run double in the fifth, another five-run inning.
Cody Spangenberg had three RBIs and the Padres had 11 hits after scoring four combined runs in a three-game sweep by San Francisco.
That was more than enough for James Shields (12-6). The right-hander allowed a run on four hits and struck out six in seven innings to become the fifth Padres' pitcher to eclipse 200 strikeouts.
Shields pitched without noticing the rain pouring into the stands behind the plate -- Chase Field's roof was closed -- in the first inning and stayed in after being struck on the right forearm in the seventh to reach 200 strikeouts for the third time in his career.
"He'll compete no matter what the score is," Padres manager Pat Murphy said. "He won't give into hitters. That's what makes him so effective."
The Diamondbacks were shell-shocked from the moment Myers hit Hellickson's 3-1 pitch out for a leadoff homer. Arizona had two errors in San Diego's five-run first and never recovered.
Paul Goldschmidt had one of Arizona's few bright spots, hitting a run-scoring double in the first inning to join Luis Gonzalez (2011-12) as the only players in team history with multiple 100-RBI seasons. Goldschmidt had 125 in 2013.
"The understand. They are embarrassed by the performance as a team, as a group, but I am sure they will bounce back," Diamondbacks manager Chip Hale said. "We always have so I am not concerned about that."
Hellickson's return from the DL because of a left hamstring strain could not have gotten off to a worse start.
After Myers' homer on a 3-1 pitch, San Diego loaded the bases on two walks and an error by third baseman Jake Lamb. Jedd Gyorko hit a sacrifice fly, then Spangenberg and Derek Norris each had run-scoring singles. Another run came in when Hellickson threw into center field trying to get Justin Upton after he left first base early.
Hellickson lasted one inning after giving up five runs -- three earned -- and three hits.
"I felt like that was all he had," Hale said. "Just not a good night for him."
The rain came after that.
A strong thunderstorm moved through downtown Phoenix and a section of about 100 seats got soaked as rain poured through Chase Field's closed roof. The fans behind the plate had to move, but it didn't affect the game before tapering off the next inning.
Shields pitched well with the comfortable lead and through the rain, giving up two hits after the first inning.
Spangenberg added a two-run double in the fifth inning and Myers followed with a three-run double to put the Padres up 10-1.
Padres: RHP Tyson Ross, Tuesday's pitcher against Arizona, allowed three home runs in his last start against Colorado. He went 16 starts earlier in the season without giving up one.
Diamondbacks: RHP Jhoulys Chacin is 5-2 with a 2.88 ERA in 12 career games against San Diego heading into Tuesday's game.