Robert Andino's two-out RBI single capped a run rally in the bottom of the ninth, and the Baltimore Orioles downed 3, ultimately sending Boston home instead of to the playoffs.
Only moments after the stunning comeback win at Camden Yards, the Tampa Bay Rays finished off an even more improbable victory over the Yankees in 12 innings. That sent Tampa Bay to the playoffs as the American League wild card participant instead of the Red Sox, who ended a game back after an awful September.
Andino followed with a two-strike flair, which Sox left fielder Carl Crawford dove for but came up with the ball on a short hop. His throw home wasn't close enough, and the O's walked off knowing they dealt a blow to the visitors' postseason hopes.
Minutes later, Evan Longoria's second homer of the game, a solo shot to left in the bottom of the 12th, capped a rally from a 7-0 deficit to give the Rays the AL wild card berth and sent the Red Sox home for good.
"We tried to stay in the moment so much," a dejected Red Sox manager Terry Francona said. "Whatever happened three weeks ago, the mess we got ourselves in, we needed to take care of business today and we didn't."
The Sox (90-72) were nine games up in the wild card standings on September 2, but crumbled under the weight of a 7-20 September and their failure to reach the postseason echoed their epic late-season collapse of 1978.
Jim Johnson (6-5) got the win by working out of a bases-loaded, one-out situation in the top of the ninth by inducing a 6-4-3 double play off the bat of Ryan Lavarnway.
"I think the way we finished overall was encouraging," Johnson said. "A day like today shows how crazy baseball can be."
J.J. Hardy hit a two-run homer for the Orioles (69-93), who, despite finishing with a losing record for the 14th straight year, finished 2011 with the satisfaction of having helped eliminate a bitter division rival.
Dustin Pedroia went 3-for-4 with a solo homer in defeat.
Davis worked a leadoff walk in the home half, and came in on Hardy's two-out, two-run homer to left to put the O's ahead by a 2-1 count.
In the next frame, Marco Scutaro doubled with one out, advanced on a grounder and scored on Baltimore starter Alfredo Simon's balk.
Pedroia's one-out solo homer in the fifth put Boston ahead once more.
The O's were denied a tying run in the fifth as Reynolds hit a leadoff double, but was erased at home trying to score on a Reimold grounder. In the sixth, Sox starter Jon Lester walked Hardy and Nick Markakis, but Vladimir Guerrero hit into a double play. Matt Wieters walked to put runners on the corners but Adam Jones weakly grounded out.
Following a scoreless seventh, in which the Red Sox led 3-2, the game was delayed by heavy rains for one hour, 26 minutes.
Baltimore put two more on against Alfredo Aceves in the home half, but failed to score. Scutaro singled with one down in the eighth but was thrown out easily at home trying to score on Crawford's double.
Baltimore took five of nine from Boston at home in 2011, but the Red Sox won 10 of the 18 games overall...Hardy finished with a career-best 30 home runs...This marked the worst final month of the season for the Red Sox since the 1952 club also finished 7-20 in September...The defeat also cemented Boston's place in history, as the club which posted the worst winning percentage from September 1 through the end of a season for any club which had been in first place on that date...Ellsbury extended his record hit streak against the O's to 36 games...The Sox finished the year with 112 homers on the road -- tops in all of baseball...Just prior to the game, the Red Sox activated pitcher Clay Buchholz from the 60-day disabled list and placed third baseman Kevin Youkilis on the 60-day DL.