C.J. Wilson allowed only two hits pitching into the eighth inning for the Texas Rangers.
The problem was all the walks the left-hander gave out that turned into Oakland runs in a 7-2 loss Monday night.
"The whole game was frustration. It's good you can't read body language or read minds, that would be bad," Wilson said. "That's how they have to beat me, is I have to make mistakes and walk a bunch of guys. I don't know why it is I pitch so bad against them. It just cracks me up."
Wilson (4-2), coming off a complete game victory at Seattle last Wednesday, walked five and hit another batter. Those accounted for four of the five runs against him.
"They take everything close. So if it's not called a strike and it's a ball, then they walk," Wilson said. "It's lawyerball. That's how they roll."
Trevor Cahill (6-0) limited Texas to one run and five hits over seven innings. He struck out seven while matching the major league lead with his sixth win and becoming the first Oakland starter since Dave Stewart 21 years ago to open the season 6-0.
Since winning nine of their first 10 games this year, the defending AL champion Rangers (18-18) have lost 17 of 26 and slipped to third place in the AL West.
"Everybody knows what's going on right now. Nobody's enjoying it. But there's a lot of baseball left to be played," outfielder David Murphy said. "We could be in a lot worse spot. We can hit a winning streak and the guys ahead of us could have a losing streak. But that wouldn't change that there's a lot of baseball left."
The Rangers have been without AL MVP Josh Hamilton since he broke a bone in his upper right arm April 12. They then lost another slugging outfielder when Nelson Cruz was put on the disabled list last week with strained right quadriceps.
The only crucial mistake by Cahill was the changeup he tried to throw on the first pitch in the fifth. Mitch Moreland pulled it into the second deck in right field for his fifth homer.
Chris Davis followed the homer with a single before Cahill retired his last nine batters, including four consecutive strikeouts during that span.
"He changes speeds, he can move the ball around on both sides of the plate, and he can sink it," Rangers manager Ron Washington said. "He's always around the plate."
Josh Willingham, in the Oakland lineup after appealing his one-game suspension for making contact with an umpire, homered and drove in five runs. His three-run homer in the third put the Athletics ahead to stay.
Willingham's sixth homer of the season, a 402-foot blast deep into the left-field seats, came after Wilson issued consecutive two-out walks. Wilson was gone after hitting Coco Crisp with a pitch to start the eighth and then walking Daric Barton for the second time in the game.
Major League Baseball earlier Monday suspended Willingham for one game and fined him an undisclosed amount for making contact with umpire Bill Miller during an argument of a called third strike Saturday night at Kansas City. Willingham, who was ejected from that game, can keep playing until the appeal process is complete.
After Wilson came out, rookie Ryan Tucker failed to retire any of the four batters he faced. Tucker allowed a two-run single to Willingham that scored Crisp and Barton, and the right-hander left with the bases loaded. Mark Ellis then hit a deep sacrifice fly to left off Brett Tomko.
"In the eighth, we couldn't get outs," Washington said. "We've got to figure out a way to get outs late in the game, something that's been biting us lately. That's got to be something we make sure we correct here."
The Rangers added an unearned run in the eighth on a throwing error by right fielder Conor Jackson, who missed the cutoff man after Michael Young's single.
Cahill improved to 8-2 with a 2.18 ERA in 11 career starts against Texas -- he has no more than four wins against any other team. Even more impressive is that the big right-hander is 3-0 with a 0.98 ERA (three earned runs over 27 2-3 innings) in four starts at hitter-friendly Rangers Ballpark.
Notes: 3B Adrian Beltre was out of the Rangers lineup for the first time this season. Beltre wanted to play, but Washington said it was just time to give him a break. Beltre was 4 for 30 (.133) his past eight games. Beltre grounded into a game-ending fielder's choice as a pinch-hitter. ... Oakland is 68-68 at Rangers Ballpark, which opened in 1994. ... The only player to start all 35 games for Texas is Young, though 24 of his starts are as the DH. ... Oakland (19-17) won three of four at home against the Rangers last week.