SAN DIEGO -- Rockies pitcher Jon Gray stepped to the plate in the top of the sixth inning Thursday night at Petco Park with a full vote of confidence from his manager. The game was tied and a runner was in scoring position with two outs, but Bud Black had not a single relief pitcher stirring in the bullpen.

The game was Gray’s, it seemed.

Turned out, not even the next half-inning was his.

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His wildness and the team’s defensive lapses in the bottom of the sixth produced five unearned runs and sent the Rockies to a 9-3 loss to the Padres in the series opener. The Rockies’ third straight defeat -- they have lost 17 of 23 since July 15 -- left them 1 1/2 games behind the Padres as the bottom two teams in the National League West square off for four games.

“We’re going out there and busting our butts, trying to win every game, every pitch,” catcher Tony Wolters said. “Baseball can beat you up a little bit, and right now we’re getting beat up. All we can do is come back the next day and try our best.”

The score was 3-3 when Gray struck out to end the top of the sixth, stranding Ryan McMahon at third base. But Gray had retired 10 of the last 11 batters he faced at that point, and the exception was when Hunter Renfroe reached on a throwing error by shortstop Trevor Story to open the fourth.

Black eschewed trying to break the tie with a pinch-hitter in favor of more innings from a pitcher with a hot hand. Black had only four bench players available, and the bullpen was a bit jelly-legged after six relievers combined to allow 11 runs over eight innings in two games at Houston before the Rockies headed to San Diego.

The strategy may have been sound, but the Rockies’ fundamentals weren’t.

In the bottom of the sixth, Gray sandwiched two outs around Francisco Mejia’s flare single. The right-hander never got the final out.

“We know that things aren’t going the way they’re supposed to,” Gray said. “We should be in a different position right now than we are. We know that.”

After the second out, Gray walked rookie Josh Naylor. Then Story made his second error when Luis Urias hit a possible inning-ending grounder his way. Story looked to second base for the short throw and a forceout, but McMahon was slow to cover the bag. So Story changed direction and rushed a wild throw to first base to allow Mejia to score and extend the inning. Gray then uncorked a run-scoring wild pitch and walked pinch-hitter Greg Garcia to get the hook, trailing 5-3 with two runners left behind.

Reliever Jairo Diaz got a comebacker from the first batter he saw, Fernando Tatis Jr., and threw wildly to first for the Rockies’ second run-scoring error of the inning. Wil Myers doubled to account for the final two unearned runs of the inning.

The Rockies hadn’t allowed five unearned runs in an inning in more than a year, since June 9 last season vs. Arizona.

The Rockies’ troubles weren’t limited to that half-inning. They were 3-for-16 with runners in scoring position. They had three straight hits in the fourth inning, but failed to score after they ran into the first out at home plate when right fielder Renfroe cut down McMahon by more than 10 feet on Wolters’ single. Gray hit into a double play to end the threat.

Yonder Alonso was erased trying to stretch a single into a double in the ninth inning, down by six runs. And Story’s two errors marked only the second multi-error game of his career.

“Guys are frustrated,” Black said. “We had decent at-bats. There were a couple [opportunities] that got away from us. To win games, you’ve got to come up with hits and on the defensive side, you’ve got to make plays.”

Said Gray: “We’ve got to take risks. We’ve got to play with a chip on our shoulder. We’ve got to be angry about it, almost, and really go out there and prove something. I think that’s where our minds should be, especially at this point in the season.”