Chris Davis hit a go-ahead two-run homer in the sixth inning and the Baltimore Orioles held on to down the lowly Houston Astros, 4-3, in the opener of a three-game series.
The Orioles were mired in a 1-5 stretch coming in and didn't necessarily break out of the slump, recording just three hits against the pitching staff with the worst ERA in baseball.
But the club drew seven walks, Davis belted his 38th home run of the season -- his first since the All-Star break -- and J.J. Hardy added a two-run single to back a strong start from Wei-Yin Chen.
Chen (6-3) yielded three runs on seven hits while walking one and striking out nine to pick up the victory and send the Astros to their fifth loss in their last six games.
Jose Altuve went 2-for-4 with two RBI and Jonathan Villar provided the other run for the Astros with a straight steal of home.
Houston scratched its top starting pitcher, Bud Norris, a day before the trade deadline, and Lucas Harrell was thrust back into the rotation after a four- game stint in the bullpen.
Harrell (5-11) had only given up one hit over the first five innings but had control issues. He issued a free pass to Nick Markakis leading off the sixth -- his fifth walk of the game -- and needed Villar to make a diving stop on Adam Jones' sharp line drive for the first out of the inning.
Davis made sure no one robbed his opposite-field shot over the left-field wall, as his first home run since July 14 gave the Orioles a 4-3 lead.
"He's a great hitter," Hardy said of Davis. "When you set the standard so high...when you struggle for a week it's like a big deal. But from the teammates' perspective we don't look at it like that."
Darren O'Day relieved Chen with a runner on base in the eighth and escaped with the Orioles in front, and Jim Johnson worked a perfect ninth to close out his 36th save of the season.
Houston went on top with a three-spot in the third frame. A pair of base hits wrapped around a bunt single loaded the bases, and Altuve followed with a two-run single through the left side.
After Jason Castro worked a walk to loaded the bags again, Chen appeared to limit the damage by striking out Chris Carter and getting ahead in the count, 1-2, on Justin Maxwell. But Chen lost track of Villar sneaking down the third- base line, and while he was in the windup, Villar raced home against the unsuspecting left-hander and slid in safely as the ball struck the back of his helmet.
"He's a baseball player, very intuitive to what's going on," Astros manager Bo Porter said of Villar.
Harrell walked the bases loaded in the fourth, and Hardy dribbled a base hit up the middle for Baltimore's first hit and first runs, cutting the Orioles' deficit to 3-2.
The Astros have never won in seven games at Camden Yards ... Villar was the first Astros rookie to steal home since Craig Biggio on July 13, 1989 against the Philadelphia Phillies ... Harrell was charged with four runs on two hits and five walks over 5 1/3 innings ... The Astros have lost the last eight games Harrell has appeared in ... Chen has not lost since May 1 -- a span of six starts ... Davis has struck out at least once in 23 straight games ... Robbie Grossman had three of Houston's seven hits.