The Baltimore Orioles ran into the good Ryan Dempster.

Dempster, who allowed eight runs twice in his first three starts for the Rangers after they acquired him in a trade three weeks ago, limited Baltimore to a first-inning run and only four hits over eight innings in AL West-leading Texas' 5-1 win Monday night.

"He was effective. Look at the swings we were taking. He kept us off-balance. He knows what he's doing," said Adam Jones, who had two of Baltimore's hits. "He kept the ball down. He kept the ball off the barrel. He was able to do what he wanted to do."

Miguel Gonzalez (5-3), who had won his previous three decisions, gave up four runs in five innings.

Gonzalez gave up hits to the first two batters he faced. But the right-hander didn't give up a run until he was unable to get out of a similar jam in the fourth.

Adrian Beltre had a leadoff single before Nelson Cruz walked. Murphy blooped a one-out single to left to tie the game at 1. Geovany Soto, who like Dempster came to Texas from the Chicago Cubs last month, followed with an RBI single before Mitch Moreland reached on an infield single. Ian Kinsler hit a sacrifice fly to make it 3-1.

"I thought Miguel was good. I thought he deserved a better fate. The game's not always fair," Orioles manager Buck Showalter said. "Dempster was just a little better. There's not a whole lot there to talk about. Their guy pitched well."

Dempster (2-1 in Texas, 7-6 overall) was pitching on extra rest after missing the weekend series in his native Canada for personal reasons. While he wasn't with the Rangers for the three games in Toronto and missed his scheduled start Saturday, he threw a bullpen session over the weekend.

In his 16 starts for the Cubs before the July 31 trade, Dempster had a 2.25 ERA and pitched eight innings twice. The last time was June 10 at Minnesota, then the right-hander had an 8.31 ERA his first three starts for the Rangers.

"I was able to settle down after the first inning and just make pitches. I had a good slider," Dempster said. "I hadn't had that the couple times I've been here."

Dempster retired the last 11 batters he faced before closer Joe Nathan, in a non-save situation, struck out the side in the ninth.

David Murphy had two RBI singles for the Rangers, who opened a 10-game homestand. All nine Texas starters had a hit.

Baltimore, which is in the hunt for one of the AL's two wild-card spots, lost for only the fifth time its last 16 games.

"Every game at this point is I'm not saying do-or-die, but damn near," Jones said. "We're trying to do something that hasn't been done here in a long time. Coming here to Texas is a big stepping stone. They're a first-place team. We need to win series at this point of the season. We've been doing it of late and we need to continue that trend."

Dempster needed only three pitches to get the first two Baltimore batters out before Nate McLouth doubled and scored on Jones' soft single. That was the only run the Orioles got.

Only two runners reached second base against Dempster after that, and the last Baltimore batter to reach was Nick Markakis with a one-out single in the fifth. Dempster struck out six and walked two while throwing 111 pitches.

"Things didn't go our way. It wasn't my best outing tonight," Gonzalez said. "We battled and obviously these guys have a good offensive team. When they have runners on base they are going to try to do any little thing to score some runs. You're going to have nights like this. Any little mistake you make, they can capitalize."

Notes: Orioles 1B/DH Jim Thome, out since July 27 with a herniated disk in his neck, will start swinging off a tee and in the cages this week. Showalter says Thome will start his rehab Wednesday in Sarasota, Fla. ... Rangers SS Elvis Andrus had a standout defensive play in the fifth when he made a backhanded stop deep in the hole and threw out Manny Machado at first base. ... Jones had two singles but is homerless in 88 at-bats. ... Markakis was 1 for 3 with a walk and is hitting .333 in 37 games as Baltimore's leadoff hitter.