BALTIMORE (AP) -- The Boston Red Sox cleared their final standings hurdle only a few minutes into their game against the Baltimore Orioles, when the scoreboard in right field let everyone know that the AL East champions were assured of home-field advantage throughout the postseason.
Oakland's loss to Seattle clinched the AL's best record for the Red Sox with one day to spare in the regular season.
''I think everybody was kind of watching,'' catcher David Ross said. ''Demp (Ryan Dempster) came out before he went to the bullpen and was just yelling that they lost. We were all laughing.''
The achievement didn't dampen the Red Sox's competitive spirit - they came from behind late before losing Saturday night's game 6-5 to the Orioles - but it was a result that hardly matters compared to the itinerary for next week.
Boston will open its division series at Fenway Park on Friday against the winner of the wild-card playoff - either Cleveland, Tampa Bay or Texas.
''We'd have liked this game to finish up a little differently,'' manager John Farrell said. ''But to know going into the postseason that for every series we go into, being able to play in front of Fenway fans and how comfortable and successful we've been at home, this is a good thing.''
Steve Pearce drove in the go-ahead runs with a double in the eighth inning for the Orioles, who earned a measure of consolation by becoming the only AL East team to win the season series against the Red Sox.
Make that a very small consolation.
''I'd trade places with 'em,'' Baltimore manager Buck Showalter said, ''and have lost the series.''
The Orioles have won 10 of 18 from the Red Sox with one to play, the second consecutive year Baltimore has taken the season series. The rest of the AL East is 21-36 against the Red Sox this season.
Pearce's drive to the left field corner - his second double of the game - came off Franklin Morales and brought home two runs. Morales had replaced Junichi Tazawa (5-4), who gave up back-to-back singles to start the inning.
Kevin Gausman (3-5) pitched 1 1-3 innings to get the win, and Jim Johnson pitched the ninth for his 49th save.
The Red Sox threatened against Johnson when Mike Napoli hit a two-out single and pinch-runner Quintin Berry stole second, but Jonny Gomes was called out on strikes to end the game.
Daniel Nava tied a career high with four hits, and Dustin Pedroia had three hits and an RBI for the Red Sox, who took a 5-4 lead with a pair of runs in the seventh.
Boston starter Jon Lester gave up four runs and nine hits over five innings. He had gone nine starts without allowing a home run, but that streak was broken by Brian Roberts' solo drive to lead off the third.
The Orioles pieced together four singles to take a 4-2 lead, but David Ross' double in the sixth cut the deficit to one and chased Baltimore starter Wei-Yin Chen.
Chen allowed three runs and nine hits over 5 1-3 innings and ended up with his sixth consecutive no-decision.
Notes: Lester flew home during the game to be with his wife, Farrah, who's scheduled to be induced with the couple's second child Sunday morning. ... Showalter had a thin bench because of injuries to OF Michael Morse and INF Jonathan Schoop. Morse has possible ligament damage in his left wrist and will see a specialist to determine whether he needs surgery, and Schoop was examined after showing symptoms of a back injury. Showalter said Schoop will play in Sunday's season finale.
Follow Joseph White on Twitter: http://twitter.com/JGWhiteAP