The A's tuned up for their final American League West showdown of the season with the second-place Texas Rangers Thursday with an easy 8-2 win over the Twins behind the two-hit one-walk one-run pitching of A.J. Griffin.

The second-year right-hander was at the top of his game striking out eight one shy of his career high before turning the last two innings over to the Oakland bullpen.

He had plenty of help from his offense which broke out for four runs in the third inning against Minnesota left-hander Scott Diamond an inning capped by a two-run triple from Yoenis Cespedes who now has RBIs in six consecutive games.

The A's will thus carry a 3½-game lead in the West into the series with the Rangers who are coming off being swept at home by Pittsburgh Monday through Wednesday. So no matter what happens in the series Oakland will head back to the Bay Area for the start of the final homestand of the regular season with the lead in the division.

Texas entered the month with a two-game lead in the West but the A's have been surging while the Rangers have been flailing. Oakland the winner of five consecutive series two of them four-game series is 8-3 in September while the Rangers are 2-8.

The resurgent Griffin retired the first nine men he faced then saw Josmil Pinto of the Twins single and Brian Dozier work him for a walk. Griffin caught a break when second baseman Alberto Callaspo speared a liner off the bat of Oswaldo Arcia and was able to double Dozier off first base to end the inning.

After that Griffin put together another streak retiring nine batters in succession before Oswaldo Arcia homered with two out in the seventh. That couldn't slow Griffin en route to his 14th win doubling his total of his 2012 rookie season.

The 25-year-old had struggled through August (1-2 with a 4.13 ERA) but he won his last start of the moth in Detroit and that seems to have turns the season around for him. He is 4-0 in his last four starts giving up 10 runs in 25 innings a 3.60 ERA. He's 14-9 with a 3.81 ERA for the season.

The A's four-run fourth started with the bottom of the order as Derek Norris doubled and Daric Barton singled. Coco Crisp's grounder got the first run in and after a Josh Donaldson walk Jed Lowrie singled home a second run.