The loss snapped the Orioles’ season-best, five-game winning streak.
Holland, who logged his 25th save in 27 chances, gave up a leadoff single in the ninth to Nick Markakis and a run-producing triple to Adam Jones with none out.
Holland preserved the victory by striking out Chris Davis, and retiring J.J. Hardy and Henry Urrutia on grounders.
Chen (4-0), who was making just his second start after replacing Luis Mendoza in the rotation, limited the Orioles to three hits and one run, retiring the final 10 batters he faced. The Orioles had bashed 45 hits in their previous three games before Chen and three Kansas City relievers shut them down.
Chen, the Royals’ 2012 opening day starter, was relegated to the bullpen to start the season after Mendoza earned the final rotation spot in spring training. In two starts, Chen has yielded one run and four hits in 12 innings.
Manny Machado homered with two outs in the third for the only run Chen permitted.
The Royals went 2 for 15 with runners in scoring position, stranding 12 runners, including nine at second and third base.
They loaded the bases with none out in the first, but scored only one run when Billy Butler grounded into a double play.
In the second, Chris Getz’s one-out single scored David Lough.
Mike Moutakas’ double into the right-field corner in the third scored Lorenzo Cain, who singled to lead off the inning. The Royals had runners at second and third with none out, but failed to pad their lead.
Jason Hammel (7-7) took the loss, giving up 10 hits in six innings for the second straight start. After starting the season 7-2, Hammel is 0-5 with a 5.47 ERA in eight starts since his last victory on May 27 at Washington.
— Associated Press —