Harden struck out a season-high nine in seven scoreless innings and dominated his former team, leading the first-place Texas Rangers to their season-best fourth straight win with a 4-2 victory over the A's on Monday night.
Harden (2-1), the hard-throwing righty who spent his first 5½ big league seasons in Oakland, didn't allow a hit until Rajai Davis' one-out double down the left-field line in the sixth. He gave up two hits in all and didn't walk a batter for the first time in his six starts.
"It's nice," Harden said. "I haven't been myself lately. This is what I want to continue here on out, this feeling."
Justin Smoak homered, Michael Young had an RBI double, Josh Hamilton singled in a run and Ryan Garko added an RBI groundout in the Rangers' fifth straight road win.
The dismal crowd of 8,874 was the A's lowest since they drew 6,295 against Seattle on April 3, 2003.
Smoak led off the ninth against Jerry Blevins with his second homer of the year, then Kevin Kouzmanoff put the A's on the board with a two-run homer in the bottom of the ninth off Frank Francisco. Neftali Feliz relieved and recorded the final three outs for his sixth save in seven chances.
Until Davis' hit, Eric Chavez was the lone baserunner to reach against Harden -- and on a controversial play in the second.
Chavez was initially called out at first even though it looked like Harden missed the base after fielding the grounder and handling the play himself. A's manager Bob Geren rushed out to argue and the call was overturned, prompting Texas manager Ron Washington to come out and argue. He was quickly ejected for the second time this year. Harden was charged with an error.
"It actually helped me. It got me going," Harden said. "I did barely nick the base, but I can see how the umpires didn't see it that way. I should have stepped on the middle of the bag. It was a mistake by me and shouldn't happen. I kind of got mad at myself."
Washington expected a warm reception in his first trip back to Oakland since admitting in March during spring training that he tried cocaine one time last season and failed a Major League Baseball drug test. Washington was the A's beloved third-base coach for 11 years.
"I think the fans love me," he said. They cheered madly, but only after Washington was tossed by crew chief Joe West.
West said the umpires gathered to go over the play and decided Harden had missed first base -- and that Washington isn't allowed to argue once the crew has come together for a consultation.
"It showed me a lot by asking and they actually got the play right," Geren said.
Washington wound up watching from his clubhouse office, saying: "It's the hardest thing I've ever had to do as a manager in a ballgame, especially after the second inning. ... You tell me Bobby Geren can argue and I can't come argue? I said something I shouldn't have."
Young had three hits, including his run-scoring double in the fifth, an encouraging sign for the third baseman after he came into the game in a 5-for-27 stretch over his previous six games.
The A's lost for the sixth time in seven games and fell 1½ games behind Texas, which followed a three-game sweep of the Mariners in Seattle with another strong performance against an AL West rival.
A's starter Dallas Braden (3-2) was tagged for a career-high 11 hits in seven innings.
Harden didn't issue a walk for the first since last July 17.
"He threw a lot better than he has all year, that's for sure," Geren said. "His velocity was up significantly from his previous starts and his command, he'd had trouble."
The A's will call up Vin Mazzaro from Triple-A Sacramento to start Tuesday in place of Justin Duchscherer, who is nursing a sore left hip. He was examined Monday in Nashville by Dr. Thomas Byrd.
Notes: Texas is 6-1 vs. the division. ... Rangers OF Nelson Cruz, on the DL with a strained right hamstring, hit for the second straight day and was set to do early defensive work and hitting Tuesday. He is scheduled to be activated when eligible May 12 after a rehab outing. ... A's assistant general manager David Forst and his wife, Rebe, welcomed their first child, son Judah, on Saturday. ... Texas SS Elvis Andrus had the day off and he is still nursing a sore calf. ... Chavez will provide food and other products to 4,000 Bay Area families Tuesday at the Coliseum through Feed The Children's "Americans Feeding Americans Caravan." A's owner Lew Wolff matched Chavez's contribution.