Harden (4-0) didn't play a major role during the regular season because he spent more than three months on the disabled list with strained elbow ligaments. But his effort against the Mariners only enhances the A's playoff prospects.
In just his eighth start, he held the Mariners to two hits and no runs over his five innings. He walked one and struck out five in his limited, 76-pitch outing. He's expected to reach the 90-pitch level Sunday against the Angels, which should set him up for the postseason rotation. Oakland is 8-0 in his starts.
"It was frustrating that I wasn't playing, but it was fun watching these guys all year, the way they play every day," Harden said. "This game was really big for us today. We had to get this out of the way. It's a really good feeling right now, a big relief."
It's also a big relief for Macha and pitching coach Curt Young, who have another tool to use in the playoffs. When Harden is healthy, he can be the most dominant pitcher on the staff.
"The fact that Rich is healthy and doing well is huge because either we can start him or it's a huge weapon in the bullpen," said veteran lefty Barry Zito. "I'm not sure what we're going to do with Rich, but it's good to have him."
Macha also isn't sure yet. He's going to stretch him out Sunday against the Angels, then decide what role he'll play.
"He missed the whole year. He put a lot of work in coming back," Macha said. "He's going to give us a boost in the playoffs. We'll see where he fits in the rotation, but he's going to need that outing to stretch out a little further."
In the clincher, Milton Bradley had a three-run, second-inning home run. Nick Swisher added his 34th home run, also in the second. Jay Payton matched his career high with four hits, while Jason Kendall had four hits and two RBIs. This is Kendall's first trip to the playoffs in his 11th big-league season.
"From start to finish since Spring Training, this team pulled together," Kendall said. "That's what it's all about, 25 guys. One guy doesn't carry us."
The A's closed the door on the Angels with a final two-month surge. The critical point came on July 29 after they beat the Blue Jays to leapfrog over the Angels into first place. Oakland followed that with victories in 14 of its next 16 games to take a 6 1/2-game lead. After Aug. 22, the Angels did not come closer than 4 1/2 games.
"We started clicking in July and August and just tried to keep that momentum in September," Zito added. "That was huge. We've overcome a lot of adversity with all the injuries."
"We've had Frank Thomas leading the way with his comeback year and everything he has to prove. There are just so many stories intertwined. As a veteran guy now, I can appreciate things a lot more."
Oakland can give a big thanks to Seattle for its crown. The A's have a 16-2 record against the Mariners this season, including a record 15 in a row.