HOUSTON — Orioles right-hander Chris Tillman can't explain it; really there's not necessarily any logical reasoning for it.
Maybe it's advanced maturity or improved focus or pure coincidence, but when Tillman takes the mound on the road this season — like he did Tuesday at Minute Maid Park in the Orioles' 4-1 victory over the Houston Astros — his team comes out on top.
Five times Tillman has pitched in opposing parks this season, and five times the Orioles (33-25) have been victorious. He is 4-0 in those games.
"It's not that I try harder on the road," said Tillman, who allowed just one run in seven innings Tuesday and has a road ERA of 2.30 compared to a a 5.31 ERA in seven home starts. "I can't put my finger on it. I really enjoy pitching in Camden Yards. I go out with the same game plan every time and try to do my best every time."
Tillman and Houston's Lucas Harrell locked into a pitcher's duel through seven innings, combining to allow just nine hits and three runs (two earned), before exiting. It was an impressive showing from two hurlers who had combined to allow nine earned runs and 16 hits in their last starts (which lasted a combined 10 1/3 innings).
"The key to that game was Tillman," said Orioles manager Buck Showalter. "And their guy pitched real well too. We were fortunate."
With the victory, the Orioles won for the first time in Houston, which joined the American League this season. Dating back eight years, the Orioles have won seven straight against the Astros, whom they swept during interleague series in Baltimore in both 2005 and 2008. The Astros swept the Orioles in Houston in 2003 — so Tuesday was the first time a road team had ever won a game in the 10 meetings between the two.
The Astros (21-38) entered Tuesday with a six-game winning streak and fresh off a four-game road sweep of the Los Angeles Angels. The Orioles have won 10 of their past 14 and have an impressive 18-12 record away from Camden Yards. They remain tied with the New York Yankees in second place in the AL East, 2 ½ games behind the Boston Red Sox. They're eight games over .500, tying a season high.
"Winning on the road requires discipline. On and off the field. Getting your rest, eating properly," Showalter said. "I think they have such a commitment to each other as teammates, they don't want to do anything that jeopardize them being in a position to make a contribution. And Chris has done a good job of that. And if that's maturity, so be it."
Tillman (5-2) pitched at least seven innings for the third time in 2013. He allowed four hits — including a Brandon Barnes' solo homer in the sixth — and two walks while throwing 113 pitches, one shy of a season high. He struck out eight batters, tying a career high that he set Sept 11, 2009 at Yankee Stadium.
"My fastball was better tonight. My other pitches set it up, though," he said. "I think I was able to mix in my off-speed stuff, cutter, changeup, and try to get them off the fastball and then take my shot with the fastball when I needed to."
The Orioles scored twice in the third against Harrell, which proved to be enough offense.
Designated hitter Danny Valencia homered to right — his third of the season in just his 25th at-bat for the Orioles, with all three coming in a span of 17 at-bats.
Valencia, who had 11 homers in 40 games at Triple-A Norfolk before being recalled May 19, had three big league homers last year in 154 at-bats with the Red Sox and Minnesota Twins.
"I just think I am a lot different hitter than I was last year," Valencia said. "Last year was a really rough season for me. I was able to look at a lot of film this offseason, work on things, try to iron out some stuff in my swing and you know, it's been kind of paying off. So I'm just happy I'm getting these hits and we're winning. It just feels a lot better."
The second run came after Manny Machado hit his major league lading 26th double of the season. He moved to third on a wild pitch and scored when Astros first baseman Chris Carter allowed an Adam Jones grounder to skip past him.
That was all the damage the Orioles could get against Harrell (4-7), who permitted five hits, two runs (one earned) and struck out six.
The Orioles picked up another unearned run in the eighth. Nate McLouth singled against reliever Wesley Wright. McLouth then stole second and third and dashed home when catcher Jason Castro threw wide to third base. McLouth is tied with Boston's Jacoby Ellsbury with an American League-leading 21 steals.
The Orioles added another run in the ninth on Ryan Flaherty's RBI single that scored J.J. Hardy. Flaherty and Adam Jones — who made two running catches while approaching Tal's Hill in center field — led another exemplary defensive effort by the Orioles.
"The thing about the hill is it starts at 410 feet away, so you got to really get it now. The first ball back I was a lot closer to it. I got a lot of ground here that I got to cover," Jones said. "But Tillman went out there and kept me on my toes, kept the whole defense on our toes. That's what happens when your pitcher goes out there and throws strikes. Good plays happen."
Relievers Tommy Hunter and Jim Johnson (19 saves) threw scoreless innings to keep the club undefeated when Tillman's on the mound in a visiting park.
"He's learning to calm down that crowd. Even when they get rallies, he's learning to take an extra second, gather himself. And the man is going out there and making great pitches," Jones said of Tillman. "I've been around Tillman for the last six, seven years and he's starting to really come into his own at this level."