The Mariners staked Iwakuma to a 7-0 lead just one night after teammate Felix Hernandez squandered a 5-0 cushion in a series-opening loss by the Mariners.
"Haren's no different than any other pitcher -- you want to get to him early and get to the bullpen," said Mariners left fielder Trayvon Robinson, who had a pair of hits including an RBI single. "He's a groundball pitcher who throws a lot of stuff out of the zone and tries to make you chase it."
Jaso made it 4-0 in the third with his seventh homer of the season, a towering drive that landed about a dozen rows back in the elevated right field seats.
It was the ninth consecutive start in which the three-time All-Star allowed a home run, the longest streak of Haren's 10-year career. It began when the Colorado Rockies hit four against him on June 9 at Coors Field -- all solo shots in Haren's 11-5 victory.
"He got me out on the at-bat before on the same pitch, when I popped out," Jaso said. "But it was up more than it was the next at-bat, and this time he dropped down a little bit. So I was able to get a little bit more extension on it. "The pitch right before that, my swing was really long and my head was flying out. So I stepped out of the box, tried to reset my bearings and just tried to be short to the ball with two strikes."
Iwakuma (3-3) allowed three runs and six hits in his seven-plus innings and struck out four in his seventh major league start. The right-hander gave up his only runs on Vernon Wells' RBI single in the fifth and a two-run homer by Wells in the eighth on his 86th and final pitch.
"The biggest thing we knew going in was that if he was effective down in the zone, it was going to be a long night," Wells said. "And it was, for the most part, because he kept the ball down."
Haren (8-9) threw 63 pitches in 3 1/3 innings and was charged with seven runs -- five earned -- and five hits. The right-hander failed to record a strikeout for only the second time in his last 261 starts. The other time was May 8 at Minnesota, when he pitched 3 2/3 innings in a 5-0 loss.
The Mariners grabbed a 3-0 lead in the second. Miguel Olivo, who came in 0 for 15 against Haren, hit a bloop single to right to put runners at the corners after a walk to Mike Carp. Robinson followed Olivo's hit with an RBI single, and another walk to No. 9 hitter Brendan Ryan loaded the bases before Dustin Ackley lined an 0-2 pitch to right-center for a two-run single.
"It just wasn't my night," said Haren, who gave up at least one homer in each of his first eight starts in 2006. "I felt great in the bullpen and the first inning went well, but I don't know what happened after that. It's not like they were blasting the ball all over the place. A couple of soft hits, then a big hit that opened the game up, and after that it was pretty much over. I really didn't see it coming."
Haren's problems continued to snowball in the fourth after Olivo singled to deep shortstop and continued to second on Erick Aybar's throwing error.
A wild pitch sent Olivo to third, and Ryan drove him in with a single after a walk and a stolen base by Robinson. Ackley followed with a routine grounder to two-time Gold Glove first baseman Albert Pujols, who misplayed the ball for his second fielding error in two nights as Robinson scored to make it 6-0. At that point, Haren was relieved by Jerome Williams, who gave up an RBI single to Jaso three batters later and finished the game.
Angels rookie phenom Mike Trout robbed Olivo of a two-run homer in the eighth inning, timing his leap perfectly at the fence in straightaway center field and throwing to first base to double off Eric Thames. But all it did was prevent the Mariners from adding on to their 7-1 lead.
"He seems to be putting himself in the right place at the right time and making spectacular plays," Wells said. "And the guys on the other side of the field are on the wrong side of the web gems right now. They can't test him anymore. They've got to pick on somebody else."
Prior to his RBI single, the last time Wells drove in a run with a hit was May 16, when he had a two-run homer against Gavin Floyd of the White Sox at Anaheim. Wells tore a ligament in his right thumb four days later and underwent surgery, keeping him sidelined until July 28. He was hitless in his first 16 at-bats off the disabled list before singling in the third inning.
"I'd rather go oh-fer and win, to be honest," Wells said. "I can deal with oh-fers if we win games. Individual stuff at this point doesn't matter. What we play this game for is to play meaningful baseball at this time of the year. Hopefully we can just win a ballgame tomorrow."
Kendrys Morales homered in the ninth against Mariners closer Tom Wilhelmsen, who was pitching in a non-save situation. ... Iwakuma has allowed one home run in each of his seven starts. He faced the Angels one other time, allowing one hit over three scoreless innings in relief on June 5 at the "Big A." ... The Angels purchased the contract of RHP Steven Geltz from Triple-A Salt Lake. A roster spot opened up for the first-time major leaguer when RHP David Carpenter was optioned to the Bees after Friday night's game. ... RHP Jordan Walden, who hasn't pitched for the Angels since July 8 because of a biceps strain, began a rehab assignment Saturday with Salt Lake.