Michael Cuddyer and Garrett Jones homered off the 20-game winner in his last start before the playoffs, leading the Minnesota Twins to a 5-4 victory over Boston on Thursday night and preventing the Red Sox from closing in on a division title.
"We still have some things we want to do," Beckett (20-7) said after losing for the first time in five starts since August. "I don't think I will be a part of it, except with my pompons."
Boston has already clinched a playoff berth, but it needs two more wins -- or Yankees losses -- to win its first AL East title since 1995. The Red Sox had their first chance on Thursday night, but the loss, combined with the Yankees' 3-1 victory over Tampa Bay, cut their lead in the AL East to two games and left their magic number at two.
"I had so much going on in our game, I had to worry about our game," said Red Sox catcher Jason Varitek, who homered in the eighth to cut the deficit to one run but struck out with the bases loaded for the second out in the ninth. "We put ourselves in position to win. Personally, I didn't get it done."
Boston's David Ortiz was 4-for-4, including his 34th homer and 51st double. He walked in the ninth to reach safely in his ninth consecutive plate appearance.
Beckett allowed five runs and 10 hits in six innings, striking out six. He had a throwing error on a foolhardy cutoff of a throw to the plate in the fifth when Torii Hunter singled to score Nick Punto and make it 4-2.
The only 20-game winner in the majors, so far, in two seasons, Beckett is a top contender for the AL Cy Young award.
"I'd be lying if I sat here and said I didn't think about that," he said. "I had a good year, but there are some other guys that have had good years, too."
"I think our guys enjoyed this game," said Twins manager Ron Gardenhire, whose team needs to win out to avoid its first losing season since 2000. "We haven't had much to smile about."
The Red Sox threatened in the eighth and again in the ninth. They cut the lead to 5-4 in the eighth on Varitek's homer and put runners on first and third before Nathan came on and got Dustin Pedroia to pop up in a brief but sudden rainstorm. With the bases loaded he struck out Varitek and pinch-hitter Kevin Youkilis to end the game.
"That's our playoff," Hunter said. "That was very exciting."
Jason Bartlett had three hits for the Twins.
Hideki Okajima pitched a scoreless eighth, striking out two, in his first appearance since Sept. 14 as the Red Sox try to bring him back from a tired arm.
"It didn't look like there was a ton of rust," Red Sox manager Terry Francona said. "So we can get him out there again."
The Twins scored a run in each of the first three innings. They added another in the fifth when Punto led off with a double, and two outs later Hunter bounced one up the middle that second baseman Pedroia kept out of center field with a diving stop.
He got up and fired home, but Beckett cut off the throw between the mound and the plate, then turned and threw wild past Varitek. Punto scored easily, and Hunter advanced to second, but Beckett retired Justin Morneau on a fly ball to center.
Boston made it 4-3 on Ortiz's homer in the bottom half, but Jones made it a two-run game in the sixth.
Beckett was 9-5 with a 4.17 ERA at home and 11-2 with a 2.18 ERA on the road. ... Former Red Sox INF Johnny Pesky celebrated his 88th birthday. ... Boston CF Coco Crisp was out of the lineup with what appeared to be a virus. ... Ortiz's 51 doubles are fourth-most in Red Sox history. It was his 50th as a DH, tying the major-league record set by Edgar Martinez in 1995. .. Boston OF Jacoby Ellsbury left the game after four innings because of muscle cramps in his right calf.