De La Rosa had won seven straight decisions and eight of his past nine, and the Rockies had won five straight. But they were no match for the Phillies, who hit three home runs off De La Rosa in a 7-0 Rockies loss at Citizens Bank Park before a sellout crowd of 45,129.
At least the loss, which allowed the Giants to leapfrog the Rockies and take a half-game lead atop the National League Wild Card standings, should be easy for De La Rosa (9-8) to forget.
After giving up seven runs and 10 hits in five innings, De La Rosa is 0-3 with a 9.78 career ERA in career six games (four starts) against the Phils, and 0-2, 15.12 in two starts at Citizens Bank Park.
"I made three mistakes in one game, and I paid for it," De La Rosa said with a shrug and a smile. "I think they know what is coming, and they always hit very good against me."
It might not have mattered if De La Rosa had pitched better. Phillies rookie lefty J.A. Happ (8-2) fanned a career-high 10 in his second career complete game.
"He hit his spots," said Dexter Fowler, who doubled and walked. "The first few innings he wasn't really hitting his spots, but from the fifth inning on, he was just spotting up.
"He'd go in, he'd go further in. Then he'd go on the black and go away."
Happ held onto his shutout by overcoming Todd Helton's leadoff double in the seventh. Happ forced fly balls by Troy Tulowitzki and Garrett Atkins, and in between struck out Brad Hawpe swinging. Helton moved to third on Tulowitzki's fly, so the strikeout of Hawpe was important.
"With him on third and one out, ideally you'd want a strikeout," Happ said. "Obviously, you can't get those at will, but I was able to get ahead. I got them to chase a ball. But then it's not over. You've got to continue to bear down. I got a popup on the next pitch."
So De La Rosa will pitch another day, like Monday against the Cubs at Coors Field. And the Rockies can still finish their 10-game road trip with a victory over the Phillies on Thursday afternoon.
But Rockies manager Jim Tracy hoped De La Rosa left the mound with a lesson learned.
Pedro Feliz and Jimmy Rollins hit solo shots in the second inning, and Jayson Werth added an opposite-field three-run shot in the fifth. All came on changeups that De La Rosa wanted to bounce. They bounced beyond the outfield walls.
"From a growth standpoint, from a development standpoint, the complete maturity of a winning pitcher comes when you go out there on a given night and you realize you have something that's not working, you have to turn the page," Tracy said.
It marked the first time De La Rosa has given up three home runs in a game since Aug. 23, 2006, for the Royals against the Indians.
De La Rosa will have one reminder of his rough night, for a few days, anyhow. Carlos Ruiz hit a smash to the mound that bounced off De La Rosa's inner left forearm in the fourth. De La Rosa stayed in until being replaced by Josh Fogg to start the sixth. Fogg, rarely used in the past month because of the starters' effectiveness, threw two scoreless frames.
De La Rosa said he'll be fine for his next start.
"I felt good today with the rest of my pitches, except for my changeup," De La Rosa said. "It happens."
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.