While they've already locked up a playoff spot, the Oakland Athletics suddenly find themselves on the verge of overtaking the Texas Rangers.

With the American League West title on the line, the surging Athletics try to sweep the Rangers as both clubs wrap up the regular season Wednesday (12:35 p.m. PT).

'As long as we believe inside this clubhouse and we know we can get it done, we're going to do it.'— Athletics closer Grant Balfour

After clinching its first post-season berth in six years during Monday's series opener, Oakland (93-68) pulled out a 3-1 victory Tuesday to move into a first-place tie with Texas (93-68).

"As long as we believe inside this clubhouse and we know we can get it done, we're going to do it. I honestly believe we're going to win tomorrow," Grant Balfour said after recording his third save in as many days. "Nothing is guaranteed, but it's about as good as. I believe we can go out and get it done."

Rangers pitcher Ryan Dempster (7-3, 4.64 earned-run average) of Gibsons, B.C., will be doing his best to prevent it from happening.

Dempster has been very good recently as long as he's not facing the Los Angeles Angels. He lost to them for the second time in September on Friday and allowed a combined nine runs over nine innings in those starts, giving up 13 hits and seven walks. Not counting those games, he's won six consecutive outings while posting a 2.04 ERA.

Including his time with the Chicago Cubs, Dempster has a 2.78 ERA on the road this season — sixth-best in the majors among qualified starters.

In his only career appearance against Oakland, Dempster allowed two runs over 6 2/3 innings of the Cubs' 6-2 victory June 16, 2010.

The loser of this game enters the post-season as one of two AL wild-card teams and will have to win a one-game playoff against Baltimore or the New York Yankees in order to advance.

Winner of five in a row, Oakland is trying to become just the fifth team to win a division or pennant after trailing by at least 13 games.

The reigning two-time division champion Rangers, meanwhile, have dropped six of eight, with four of those losses coming to Oakland.

The A's have to be feeling good about giving the ball to rookie A.J. Griffin (7-1, 2.71 ERA), having won 10 of his last 12 outings. The right-hander yielded one run over 5 2/3 innings Friday in an 8-2 victory over Seattle, improving to 3-0 with a 2.52 ERA in seven starts by the Bay.

Texas slugger Josh Hamilton has not homered in eight straight games to remain stuck on 43, one shy of Miguel Cabrera's AL lead but needing two to possibly prevent the Detroit star from winning the Triple Crown.