SEATTLE -- Oakland's Yoenis Cespedes was happy to be back in the outfield on Friday night and showed it by hitting two home runs in the Athletics' 6-3 win over the Seattle Mariners.
The A's scored all of their runs on four homers while helping starter Bartolo Colon extend his winning streak to seven consecutive starts.
Colon (10-2) gave up his first home run since May 14, but the three-run shot he allowed to Nick Franklin in the third inning accounted for Seattle's only runs. Colon, who had given up three runs in his previous five starts, scattered seven hits while striking out four in eight innings.
"Kind of a typical Bartolo start," A's manager Bob Melvin said. "The shocker was he gave up a home run."
Mariners starter Hisashi Iwakuma gave up a season-high three home runs, including a Coco Crisp shot that led off the sixth to give Oakland (44-32) a 4-3 lead.
Iwakuma (7-3) allowed six hits and struck out six while taking his second consecutive loss. He said afterward that all three home runs came on his signature pitch: the split-finger fastball.
"Overall, I felt pretty good on the mound," Iwakuma said through Mariners translator Antony Suzuki. "It's just that the home runs today weren't where I wanted (the pitches), location-wise, and it cost me."
Trailing by one run, Seattle (32-43) ran itself out of opportunities in back-to-back innings, with base-running gaffes in the sixth and seventh.
Kyle Seager tried to go from first to third on a passed ball and was easily thrown out when A's catcher Derek Norris cleanly fielded the ball off the wall behind home plate and threw to third for the first out of the inning.
One inning later, the Mariners' Michael Saunders led off with a single but was caught stealing when he started running to second before Colon began his windup. Colon turned and caught Saunders breaking to second, then threw him out at first base when Saunders tried to get back.
Seattle reliever Charlie Furbush struck out the side in the top of the eighth to give the Mariners another chance before Colon got through a perfect eighth on 11 pitches.
Cespedes hit his second home run of the game off Mariners reliever Tom Wilhelmsen in the ninth. The two-run homer put Oakland ahead 6-3 and gave Cespedes his third multi-home run game this month.
"Both of them were huge," Melvin said. "One of them gave us the lead; the other one extends the lead and made things easier in the ninth."
Colon had served as Oakland's designated hitter for more than a week while he battled a sore hamstring, but Melvin put him back in the field.
"He likes to play the outfield," Melvin said. "You could see it in his whole demeanor; he was just in a better mood."
Wilhelmsen, who was Seattle's closer for the first 2 1/2 months of the season, has now given up 13 earned runs in eight innings during June.
Oakland closer Grant Balfour pitched a scoreless ninth to convert his 18th save in as many opportunities this season. His current streak of converting 36 consecutive save opportunities, which dates to last season, is the second longest in club history.
Colon now has 11 career victories at Safeco Field, the most among opposing pitchers.
A matchup of dominant starting pitchers was quickly overshadowed by towering home runs in the early innings, when the two teams combined for three long balls over the first 3 1/2 innings.
Cespedes started it with a mammoth two-run shot into the upper deck in left-center field, giving the A's a 2-0 lead in the first inning. Seth Smith had singled earlier in the inning.
Franklin did Cespedes one better with a three-run shot in the bottom of the third for a 3-2 Seattle lead. Franklin's 400-foot home run to right-center field was the first homer off Colon since May 14, covering a span of six starts and 47 2/3 innings. The three runs scored matched the combined total of runs Colon had allowed over his last five starts.
"I was just hoping for something to hit to the outfield," Franklin said, "and luckily (Colon) left the changeup up."
Jed Lowrie tied the score 3-3 with a leadoff homer in the third, taking Seattle starter Iwakuma deep for Oakland's second home run of the game. It marked the team-high 12th homer hit off Iwakuma this season.
Iwakuma and Colon entered the game with a combined 14-4 record on the season while boasting sub-3.00 ERAs. Iwakuma ranked second in the AL with a 2.09 ERA before Friday's game, and Colon had posted a 0.92 ERA in his previous five starts.
NOTES: A's C John Jaso was a last-minute scratch for Friday's game due to an abrasion on his left palm. Norris replaced him in the lineup, and Smith was moved up five spots into Jaso's No. 2 hole in the batting order. ... Mariners RHP Taijuan Walker, a 20-year-old starter who was No. 18 on Baseball America's 2013 list of top prospects, was promoted from Double-A to Triple-A Tacoma. Walker went 4-7 with a 2.46 ERA in 14 starts at Double-A Jackson. ... Morse (quad) was not in the lineup for the second consecutive day, although he was called into pinch-hitting duties the previous night. ... Entering Friday night's game, the A's had the American League's best record in night games at 31-16.