A rare letdown by the bullpen kept the St. Louis Cardinals from moving into first place alone.The relief corps was touched up for four runs in the eighth inning of a 6-2 loss to the Colorado Rockies on Monday night.Charlie Blackmon had three hits and three RBIs for the Rockies, who prevented the Cardinals from taking over sole possession of the NL Central lead. They remained tied with the Pittsburgh Pirates, who lost 2-0 to San Diego."You can't be perfect all the time. It isn't that way in baseball," said John Axford, one of three relievers roughed up by Colorado in the eighth. "There are going to be tough games and there's going to be good ones and tonight was just one of the tough ones."Todd Helton started his final homestand with a key single during the decisive rally for the Rockies.Trevor Rosenthal, who has limited opposing hitters to a .203 batting average, allowed four runs and three hits in the eighth. Axford came on and gave up a two-out, two-run single."Overall our bullpen has been very, very good," St. Louis manager Mike Matheny said. "They just need to stick with what they know is right and they will be just where they've been all season."They will bounce back," he added.Troy Tulowitzki led off the eighth with a walk against Rosenthal (2-4), and one out later Helton singled to center to put runners at the corners. Wilin Rosario singled to give Colorado a 3-2 lead.Helton was caught in a rundown between third and home for the second out, but Blackmon doubled to right to score Josh Rutledge from first to make it 4-2.Helton was playing in front of Colorado fans for the first time since he announced his plans to retire at the end of the season, his 17th. He went public Saturday when the Rockies were in Arizona, and Monday afternoon the team held a formal press conference.The first baseman received a standing ovation when he came to the plate in the first inning, and Cardinals starter Lance Lynn stood behind the mound and waited as the crowd saluted Helton."Todd had a huge hit," Rockies manager Walt Weiss said. "I don't expect anything different. I think he's going to have a huge homestand."Pinch-hitter Ryan Wheeler's two-run single off Axford gave the Rockies a 6-2 cushion."We made good pitches that ended up being hits," Axford said. "I had a pitch that I thought could have been a double play and it turned out to be a flare into right field."Matt Carpenter and Matt Adams had two hits each for the Cardinals.Lynn got stronger as the game progressed. He scattered four hits over six innings and didn't let a runner past first after Tulowitzki's first-inning double before running into trouble in the seventh."Lynn was as good as we've seen him throw," Matheny said. "He had good, late, heavy movement with his fastball and was good with his secondary pitches."Collin McHugh started for Colorado in place of lefty Jorge De La Rosa, who has a sore thumb on his pitching hand that forced him to miss his turn in the rotation. McHugh allowed one run and four hits, with the only damage coming on David Freese's RBI single in the fifth.He left after throwing 75 pitches in five innings.After Lynn retired Helton in a nine-pitch at-bat, Rosario singled and moved to third on Rutledge's bloop single to right.Left-hander Kevin Siegrist relieved Lynn, and Blackmon lined an RBI single over the pulled-in infield to give the Rockies a 2-1 lead."He throws really hard so I was trying to catch up to a fastball," Blackmon said. "I knew that was going to be a tough at-bat, just trying to battle from the start and get a good swing on it."The Cardinals tied it in the eighth on Carpenter's RBI double off Chad Bettis (1-3) that scored pinch-runner Pete Kozma from second.The Rockies took a 1-0 lead in the first on Tulowitzki's RBI double.NOTES: Cardinals OF Matt Holliday entered hitting .358 against his former team. ... Adams has consecutive multihit games. ... Carpenter has an eight-game hitting streak.