BALTIMORE -- The Colorado Rockies used the Orioles' favorite weapon to hand Baltimore another painful defeat.
Colorado hit four home runs, including a tiebreaking, two-run shot by Wilin Rosario in the seventh inning, and stretched Baltimore's losing streak to four with a 6-3 victory Friday night.
After ending a 14-year run of losing seasons last year, the Orioles are seeking a return trip to the playoffs. Their current skid is not helping.
"I think this is honestly something that we needed, kind of a kick in the pants to wake us up," center fielder Adam Jones said. "We're in a unique position, in back-to-back years trying to do something special. Last year, everybody said we couldn't. This year, we created the expectation. This is something you've got to go through to get to it."
Blackmon's drive was the 73rd in the history of Camden Yards to land on Eutaw Street beyond the right-field wall. Since Colorado hasn't played in Baltimore since 2007, the significance of the homer was lost on Blackmon.
"I don't really know anything about it. They were telling me after the game that it's cool if you can do it," he said. "They'll give you a plaque out there with your name on it, and there's not a whole lot of plaques with my name on it going up anywhere."
Juan Nicasio (7-6) allowed two runs, four hits and four walks over six innings to earn his first win in five starts since July 20. The right-hander yielded 15 runs over 14 innings in his previous three outings and was 0-3 with a 7.79 ERA in four interleague starts this season.
Wei-Yin Chen (6-6) retired 12 of his first 13 batters but couldn't get out of the seventh inning. He gave up four runs and five hits in 6 1/3 innings in losing his third straight start. It was only the second time in 15 starts this season that Chen allowed more than three runs.
"Early innings I felt really good, but had some trouble in the late innings," Chen said through a translator. "I feel bad because it's my fault. I couldn't keep the guys in the ballgame. But tomorrow is another day and we still have 41 games to go."
The Orioles were coming off three straight one-run defeats in Arizona and hoping to get back on track at home against a sub-.500 team. But the Rockies bounced back from a 2-0 deficit by scoring in the fifth through ninth innings.
"It's a cozy park, but you've still got to hit it," manager Walt Weiss said. "We put some good swings on it."
With the score tied at 2 in the seventh, Chen walked leadoff hitter Michael Cuddyer and Rosario hit the left-hander's next pitch over the 25-foot scoreboard in right field.
Blackmon made it 5-2 in the eighth with a pinch-hit homer off Francisco Rodriguez.
Helton connected in the ninth off struggling reliever Jim Johnson. The drive lifted him past Joe DiMaggio into sole possession of 76th place on the career home run list with 362.
Wieters homered in the bottom half against Rex Brothers.
The game started well for the Orioles. McLouth hit Nicasio's third pitch into the bleachers, his 12th career leadoff homer and second this year.
Baltimore went up 2-0 in the third when Jones singled in a run to break an 0-for-15 skid. Nicasio then retired Nick Markakis and Wieters with the bases loaded.
Chen was in complete control early. After Troy Tulowitzki hit a one-out double in the first, the left-hander retired 10 straight batters before Rosario doubled leading off the fifth. One batter later, Nolan Arenado delivered an RBI single.
Culberson connected in the sixth to tie it at 2.
After the game, the Orioles optioned OF Henry Urrutia to Triple-A Norfolk. They are expected to recall a reliever on Saturday. ... Rodriguez left in the eighth inning with a strained right groin. ... Blackmon is 5 for 13 as a pinch hitter. ... Baltimore pitching coach Rick Adair went on a leave of absence to resolve some personal issues and was replaced by bullpen coach Bill Castro. ... Bud Norris takes the mound for the Orioles on Saturday night in the second game of the series. Chad Bettis makes his fourth big league start for the Rockies. ... J.J. Hardy's 11-game hitting streak ended, as did teammate Brian Roberts' run of three straight multihit games for Baltimore.