DENVER -- A long rain delay and a rookie pitcher kept Colorado's streaky offense in check.
The Rockies scored 30 runs in their four-game weekend series with the Los Angeles Dodgers but couldn't keep the momentum going against San Diego rookie Anthony Bass.
Making his major league debut, Bass held Colorado to one run over five innings Monday night in the Padres' 3-1 victory in a game delayed 83 minutes by heavy rain in the sixth.
Colorado's offense struggled before its outburst against the Dodgers, scoring just 16 runs in a nine-game stretch. The weekend seemed to get the Rockies back on track, but they went quiet against the Padres.
"The game's like that. You're going to score runs some days, some days you're not," Todd Helton said. "But you still have to have better at-bats. Even if they don't produce runs you still need to put together better at-bats."
The loss was the Rockies' third straight after they had won three in a row for the first time in nearly two months.
The blame was squarely on the offense.
"We had some opportunities offensively but we expanded our strike zone and basically got ourselves out," manager Jim Tracy said. "When you have a young kid out there making his major league debut and you expand your strike zone and get yourself out, you're doing him a favor."
Aaron Cook (0-1) had his second consecutive hard-luck start, and both have come against San Diego. Cook got a no-decision in his season debut Wednesday, and Monday he was tagged with the loss. He gave up two earned runs on five hits and struck out two, pitching his way out of a big inning after loading the bases with no outs in the first.
"The first inning I was flat, and I was really concentrating on keeping my ball down after that," he said. "Fortunately, I was able to get out of the first inning with one run and I really settled in after that."
The Rockies tied it in the fourth when Ty Wigginton drew a two-out walk, stole second and came home on Charlie Blackmon's single.
They had a chance to go ahead in the fifth when Carlos Gonzalez and Chris Nelson led off with singles and a flyout by Helton moved both runners up. But Troy Tulowitzki followed with a comebacker to Bass, who threw out Gonzalez at the plate.
"Very frustrating," Helton said. "We need to string better at-bats together and put more runs on the board. (Bass) pitched a good game tonight. If we would have swung the bats better we would have won the game."
The Padres took the lead again in the sixth when Jason Bartlett drew a one-out walk, Chase Headley hit a ground-rule double to left and Bartlett came home on Ryan Ludwick's groundout.
After Anthony Rizzo walked, the light rain turned heavy and play was halted. After the game resumed, reliever Matt Belisle struck out Nick Hundley to end the inning.
"Those two walks in the last inning really killed me and put us in a bad spot, giving them that extra run right there," Cook said. "If I could have got them to put the ball in play instead of walking them we might still be playing."
The Padres added an insurance run in the ninth, and Heath Bell got three outs for his 18th save in 19 chances. He was the last of three relievers that held Colorado hitless over the final three innings.
"From the sixth inning on we got two base on balls. That's it," Tracy said. "We did everything we could to stay in the game to give us a chance."
NOTES: Rockies OF Dexter Fowler (abdominal strain) could be sent to Triple-A Colorado Springs on Tuesday. Tracy said he won't rush Fowler back into the lineup, preferring to let him hone his swing on that level. ... San Diego improved to 16-12 on the road, one of the top marks in the NL. ... Bass was sent back to the minors after the game.