SAN DIEGO -- The San Diego Padres sure didn't look like a first-place team on Tuesday night.
Catcher Miguel Olivo committed two critical errors and the NL West-leading Padres walked 10 as they lost 6-5 to the last-place Colorado Rockies. Colorado's Todd Helton reached base five times and scored twice.
The Padres (68-69) again dropped below .500, making this the latest in a season a team has led a division with a losing record.
"We shot ourselves in the foot a couple innings there, and that was the difference in the ballgame," manager Bruce Bochy said. "We fought hard to try to get back to winning the game, and came close, but bottom line is we didn't play well tonight."
But the Padres remained five games ahead of San Francisco, which lost 4-2 to Los Angeles in 12 innings.
Olivo committed a pair of two-base errors in the seventh that allowed the Rockies to score two unearned runs and take a 6-0 lead. San Diego then rallied for four runs in the bottom of the seventh before pulling to 6-5 in the eighth. San Diego's Mark Loretta had four hits and two RBI.
Rockies closer Brian Fuentes walked two batters with two out in the ninth to load the bases before striking out Khalil Greene to earn his 26th save in 29 chances.
The last-place Rockies, coming off a sweep of the Los Angeles Dodgers, have won three of four games in San Diego since Aug. 26. Each team committed three errors.
Cory Sullivan drew a leadoff walk in the Rockies' seventh and took third on Olivo's errant pickoff throw that skipped past first baseman Robert Fick and into the right field corner. Helton walked, and Matt Holliday hit a sacrifice fly to left. Ryan Klesko's throw home was up the first-base line. After Olivo fielded it, he turned toward home, then, inexplicably, instead of throwing the ball back to the pitcher, flipped it to a bat boy near the Padres' dugout. Helton was waved in from second base.
Olivo wasn't at his locker when the clubhouse was opened to reporters.
Bochy, a former big league catcher, wasn't able to explain Olivo's actions.
"I guess he thought the play was dead and he was throwing the ball out," Bochy said. "I don't know why. I think we were probably as surprised as anybody.
"He just didn't call time out before he threw the ball away. You have to, and it's something he'll learn from, but that inning he made a couple of mistakes there that cost us a couple of runs."
The Padres pulled to 6-4 in their half of the inning before Eric Young struck out on a checked swing with runners on first and third. The Rockies committed two errors in the inning. Loretta hit a two-run, bases-loaded single, Dave Roberts had an RBI single and pinch-hitter Ben Johnson had an RBI grounder.
Joe Randa led off the Padres' eighth with a triple to the gap in right-center and scored on Greene's sacrifice fly.
Helton, who's hitting .452 against San Diego this year, had three hits, two walks and drove in a run. Right-hander Aaron Cook (4-1) won his fourth straight decision. He allowed six hits and two runs, one earned, in six innings.
"We didn't play our best," Rockies manager Clint Hurdle said. "We wobbled out of the bullpen, we got six runs on six hits and 10 walks, which probably wasn't very artistic from an offensive standpoint, but we played better than the other team tonight."
The Rockies had two two-out rallies against Chan Ho Park (4-2), whose three-game winning streak ended.
Helton doubled with two outs in the first to start a three-run rally. Park walked Holliday and Brad Hawpe to load the bases before Garrett Atkins hit a two-run, broken-bat blooper that fell in between shortstop Greene and second baseman Loretta. Luis Gonzalez drove in the third run when he reached on an infield single to shortstop.
Park struck out the first two batters in the fourth, then walked Clint Barmes, who took third on Cory Sullivan's single to right and scored on Helton's single to right.
Park allowed four runs and six hits in five innings, struck out five and walked four.
Padres ace Jake Peavy had his sore right shoulder examined on Tuesday. He's due to pitch in the bullpen on Thursday and then be re-evaluated. He's currently scheduled to start at Los Angeles on Saturday. ... Rancho Buena Vista, which finished third in the Little League World Series, was honored before the game. Padres owner John Moores gave the players gloves embroidered with their names.