SEATTLE -- Hisashi Iwakuma hasn't needed a whole lot of offensive help this season, but the Seattle Mariners provided some on Friday night.
Seattle broke out of a three-game offensive slump by opening a big early lead and Iwakuma did the rest, pitching the Mariners to a 6-3 victory and handing the struggling Oakland A's their season-worst fifth consecutive loss.
The Mariners (17-19) jumped out to a 6-0 lead in the fifth inning, exceeding the cumulative run total they scored in their three previous games. Raul Ibanez hit a three-run homer, and Kendrys Morales and Justin Smoak both added RBI doubles to give Iwakuma more than enough cushion.
Iwakuma allowed four hits and two earned runs in seven innings, marking the sixth time in eight starts this season that he has given up two runs or fewer. He had nine strikeouts without allowing a walk.
Iwakuma (4-1) pitched five scoreless innings of one-hit ball before the A's got to him in the sixth.
After giving up a single to John Jaso to lead off the game, Iwakuma retired 16 consecutive batters. That streak ended when Oakland's Eric Sogard reached on a sixth-inning single to shortstop that originally was ruled an error. Jaso followed with a bloop single to left, and Jed Lowrie's two-out double gave the A's their first two runs of the game to cut the Seattle lead to 6-2.
The change in official scoring, which came one at-bat after Sogard's sharply-hit grounder bounced off the glove of Mariners shortstop Brendan Ryan, ended up turning what would have been two unearned runs into earned runs. Iwakuma's ERA now stands at 1.74; had the error stood, his season ERA would be 1.39.
Left-hander Oliver Perez came on in relief of Iwakuma to start the eighth, only to give up a solo home run to Oakland's Derek Norris on his second pitch. Perez struck out the next three batters he faced before closer Tom Wilhelmsen picked up his 10th save with a perfect ninth.
Kyle Seager scored three runs for the Mariners, who were held to two runs or fewer in each of their previous three games.
Oakland (18-19) continued its own offensive struggles with just five hits. The A's have scored three runs or fewer in all five games of the current losing streak.
Oakland has now lost 15 of its past 21 games.
The Mariners jumped on Oakland starter Dan Straily early. A one-out walk to Seager in the first was followed by three consecutive hits. Smoak's RBI double gave Seattle a 2-0 lead before Straily retired two consecutive batters to get out of the inning.
Raul Ibanez hit a two-out, three-run homer in the third to extend the lead to 5-0.
Iwakuma gave up a single to Jaso to start the game before retiring the next 15 batters he faced heading into the fifth.
Morales padded the lead with an RBI double in the bottom of the fifth, giving the Mariners a 6-0 advantage.
NOTES: Jaso led off the game with a single, becoming the third leadoff hitter in Iwakuma's last three starts to reach base. Iwakuma got out of all three first innings without allowing a run. ... Going into the game, Seattle had already matched the franchise's season-high total of five home runs to lead off games. Michael Saunders almost broke the record on an 0-2 pitch Friday night, but A's left fielder Seth Smith caught his high fly ball on the warning track. ... Mariners third-base coach Jeff Datz rejoined the team but did not serve in his usual role. Datz is still dealing with cancer and has not coached in a week and a half. Former Triple-A manager Daren Brown is currently filling in as the Mariners' third-base coach.