He came away with mixed emotions after dominating his former team.
Haren allowed one run and drove in three as the Diamondbacks routed the Athletics 11-1 on Wednesday night.
"It was a little weird," Haren said. "A lot of those guys are still really close friends for me."
One of his closest friends is Joe Blanton, who lasted only three innings, his shortest outing since May 25, 2005. Haren helped drive Blanton (3-10) from the game with a bases-clearing double in the third.
"It was kind of bittersweet," Haren said. "Obviously, I want to win the game. But Blanton is one of my best friends. Those games happen."
Haren (7-4) limited the A's to four hits in seven innings, walking one and striking out eight. Haren also hit a three-run double as the Diamondbacks paid back the A's for a 15-1 drubbing in the series opener.
"Kind of flipped from yesterday's game," Arizona manager Bob Melvin said. "Hopefully, today's something to build on."
The Diamondbacks gave Haren all the support he'd need with five runs in the first.
Blanton retired the next two batters before Young hit a 1-1 pitch 412 feet into the left field bleachers to give the Diamondbacks a 5-0 lead. It was Young's 13th homer, and his first since May 31.
"They scored early off our starter and we gave a big lead to a good pitcher on the other side and he took advantage of it," Oakland manager Bob Geren said. "We got out of the game pretty early and we never got back into it."
Drew, Hudson and Tracy each had three hits for Arizona, which matched a season high with 15.
"We've been waiting to bust out for a while," Haren said.
Acquired from Oakland last winter in an eight-player deal, Haren gave up a one-out single and walk in the first but then retired the next 12 batters.
Throwing more cutters than normal, Haren cruised until the seventh, when he gave up a two-out double to Carlos Gonzalez and an RBI single to Kurt Suzuki.
"I played behind [Haren] for three years, but it doesn't prepare you to face a guy that has stuff like that," A's shortstop Bobby Crosby said. "I knew we were going to have a battle."
Haren, who entered hitting .133 (4-for-30), added to his lead in the third. With the bases loaded and two out, he lined a double over Gonzalez's head in center field to clear the bases and put the Diamondbacks ahead 8-0.
"I just tried to put the bat on the ball," Haren said. "You know, the outfielders play in most of the time on me. If I hit a good one, I get it by them."
Three of Haren's four hits this season have been doubles.
Drew added a two-run homer in the fifth against Chad Gaudin.
Blanton, who allowed eight runs in three innings, left without speaking to reporters. He lost his fourth straight start and is 1-6 since May 2.
"It just seems like the location of pitches were obviously not where he wanted them," Geren said.
Blanton's 10th loss came on June 18, the earliest date for an Oakland pitcher to lose his 10th game. ... Oakland RF Ryan Sweeney singled in the first to extend his hitting streak to 12 games. ... Arizona LF Eric Byrnes, who is out with injuries to both hamstrings, will start a three-day rehab assignment at Class A Visalia on Thursday. He's expected to rejoin the Diamondbacks on Monday in Boston, and slumping RF Justin Upton is a candidate to be optioned to the minors to make room for Byrnes on the roster. Upton, who has 84 strikeouts in 225 at-bats, was benched Wednesday night, but manager Bob Melvin said he'd be back in the lineup Thursday.