Mark Ellis had three hits and drove in two runs for the A's and Daric Barton added a two-run double.
"Cliff has a little power but that's not exactly his game," Ellis said of his double play partner. "He's getting a lot better and he'll continue to get better. He's slowed himself down. When he first came up it seemed like he was in a hurry."
Mike Sweeney homered and had four hits for the Mariners, who had their four-game winning streak end. Jose Lopez also homered and Rob Johnson added a two-run single.
"It was little things in the game that cost us, but it's always going to be about starting pitching and how deep you can get in there," Mariners' manager Don Wakamatsu said. "We've proven that over and over and we really didn't set the tone with the starting pitching."
Brett Anderson (8-10) pitched five innings, giving up three runs on seven innings. He walked two and struck out six. Andrew Bailey recorded the final four outs for his 22nd save in 26 chances.
"I lost it a little with my command and it became a grind out there," Anderson said. "I was fortunate enough to get through five innings and get a win out of it."
Luke French (4-5) allowed five runs on seven hits over 3 2-3 innings. He walked three and did not strike out a batter.
Suzuki had three hits and needs just one more for 2,000. Six more will give him 200 on the season and continue his own major-league record for consecutive seasons (9) with at least that many.
"I'm always antsy when Ichiro is up there," Anderson said. "I hate facing that guy the way he hits. It's not a good matchup for me. He's one of the toughest guys to face because he always finds a way to get the bat on the ball."
Sweeney homered to lead off the second, sparking a three-run rally. Adrian Beltre walked, Jack Wilson singled and Josh Wilson walked ahead of Johnson's two-run single.
"Offensively, I thought we had a good approach," Wakamatsu said. "Anderson has a chance to have a real bright future, and I thought we had a decent approach with the three runs early in the ballgame. If we can tack on another run there, a different ballgame, but I thought their bullpen did a nice job overall."
The A's answered with a four-run third. After Pennington's home run, Adam Kennedy doubled and Rajai Davis singled before Suzuki hit a sacrifice fly and Scott Hairston followed with an RBI groundout.
"Pennington set the tone with a big home run early," A's manager Bob Geren said. "He won't be a big home run guy but he can play little ball, bunt, run and plays solid defense. That's a pretty good player."
Kennedy's single in the fourth made it 5-3.
"Things aren't going real well the last couple starts, but that's just the way it is sometimes," French said. "I'm learning. This whole thing is still new to me, so you learn as you go. I know I need to be aggressive and attack hitters."
Bailey came on to get the final out of the eighth, before the A's scored four runs in their half.
Ellis and Barton each hit a two-run double to make 9-3 before hit a two-run homer in the ninth.
NOTES: French has allowed 12 runs over his last 8 2-3 innings after allowing 14 through his first 28 with the Mariners. ... Over 500 breast cancer survivors were honored before the game, and pink was the dominant color among the announced crowd of 16,495. ... Suzuki moved past Hall of Famer Jimmy Collins for 259th on the career hit list with 1,999. ... Mike Sweeney has a hit in 11 of his last 13 games, including seven multi-hit games. ... Anderson won his first game in Oakland since June 29, a span of six home starts. ... Bailey had a 12-inning scoreless streak snapped.Sign up for breaking news alerts from FOXSports.com!