Boston (93-65) beat Cleveland (79-79) on Tuesday to guarantee its fifth trip to the postseason in six years, a span that includes two World Series championships. The Red Sox kept things going on Wednesday, withstanding two errors and a late Indians rally to emerge with a 5-4 triumph.

Pinch-hitter Jeff Bailey tripled and scored on Mark Kotsay's double to break an eighth-inning tie as the Red Sox won for the fourth time in six games.

Boston also preserved its slim chances of a second straight AL East title. First-place Tampa Bay won 11-6 at Baltimore on Wednesday to maintain its three-game division lead, but reduce its magic number to one.

"We're still trying to play and win the division," said Red Sox second baseman Dustin Pedroia, who had two hits including his 54th double and also notched his 20th stolen base. "Guys are still going to come out and play hard. ... But we'll be ready to go."

Even if Boston doesn't come away with the division crown, it's still assured a wild-card berth and will start preparing for the AL division series, likely handing the ball to Lester (15-6, 3.26 ERA) for one of the first games in that set.

But Lester, who is 1-0 with a 1.93 ERA in three postseason appearances, must first bounce back from his first loss of the month.

The left-hander, who compiled a 0.87 ERA in winning his first three September starts, was tagged for five runs and eight hits over seven innings of a 6-3 defeat on Saturday at Toronto. He also walked three and hit a batter.

"They did a good job of hitting some good pitches. I just didn't do a good job of keeping it in control," Lester told the Red Sox's official Web site.

Lester also had some command issues in his last outing against the Indians, walking a career high-tying five. However, he escaped without a decision after allowing four runs and five hits over 4 1-3 innings of a 6-4 win on April 14 at Cleveland. He is 1-0 with a 4.96 ERA in three lifetime starts versus the Tribe.

Cleveland has dropped back-to-back contests following a seven-game winning streak. On Wednesday, the Indians totaled 13 hits, but went 4-for-12 with runners in scoring position and left nine on base.

"We had our chances," Cleveland manager Eric Wedge told the team's official Web site. "Ultimately, we weren't able to push it over the top."

The Indians now send out Jeremy Sowers (4-8, 5.48), who is trying to win three straight decisions for the first time since a four-game stretch Aug. 13-Sept. 5, 2006.

The left-hander, who is 2-0 with a 2.65 ERA in his last three starts, held Detroit to a run and five hits over six innings of a 6-3 home victory on Saturday.

Sowers is 0-1 with a 5.06 ERA in two career outings against the Red Sox, but hasn't faced them since a 4-2 loss in Boston on May 29, 2007.