Boston - Now comes the really hard part for the Boston Red Sox: four more games against the Tampa Bay Rays.

The Red Sox lost for the sixth time in seven games, wasting an eighth-inning lead when Adam Loewen's two-run single off hard-throwing Daniel Bard lifted the Toronto Blue Jays to a 5-4 win Wednesday.

"It's just another loss. I don't think it's any tougher than any other loss," first baseman Adrian Gonzalez said. "We've got to find a way in the next series to play better baseball."

Just 3-10 in September, the Red Sox began the day with a four-game lead over Tampa Bay in the AL wild-card race. Boston led the AL East at the start of the month and was nine games ahead of the third-place Rays.

After getting swept in a three-game series at Tampa Bay last weekend, Boston hosts the Rays in a four-game series starting Thursday night.

"Very frustrating," said Bard, 0-3 with a 30.86 ERA in his last three appearances. "I've been through it before. "Sometimes the effects are magnified by how big the games are."

Boston led 4-2 in the eighth before Toronto came back against the hard-throwing Bard (2-8), who entered and walked Edwin Encarnacion and Kelly Johnson.

Mark Teahen bunted, and Bard's throw to first pulled Lars Anderson off the bag for a throwing error that loaded the bases.

J.P. Arencibia's RBI groundout cut the lead to 4-3, with third baseman Kevin Youkilis bobbling the ball and throwing to first. Loewen followed with a single to center.

Loewen, converted to outfielder from pitcher, was 0-1 with a 6.63 ERA in four starts against the Red Sox for Baltimore in 2006 and '07.

"I'm very aware of that. They got me," he said, dressed in a ballerina costume as spoke to the media, part of late-season rookie hazing. "I think the best chance I had was against (Josh) Beckett in our place. I came out of the game (ahead) 2-1 in the sixth, and they ended up winning it in the top of the ninth."

Loewen has taken advantage for openings created by injuries.

"September is about taking a look at all of our personnel and he's capitalized on every opportunity, so there's no reason to think that's not going to still be in the rotation and in the mix," Toronto manager John Farrell said.

Ricky Romero (15-10) allowed four runs - three earned - and six hits in eight innings. He improved to 8-1 in his last 10 starts.

Frank Francisco pitched a 1-2-3 ninth for his 15th save in 19 chances as the Blue Jays won for just the third time in nine games at Fenway Park this season.

Red Sox starter John Lackey gave up two runs and seven hits in 5 1-3 innings. He threw 115 pitches.

"He had a high pitch count, mainly early," Boston manager Terry Francona said. "When he came out of the game, we had a good chance to win."

Toronto took a 2-0 lead in the first on consecutive run-scoring singles by Encarnacion and Johnson, but Boston tied it in the second when Ryan Lavarnway reached on a run-scoring error by third baseman Brett Lawrie and an RBI grounder by Jason Varitek.

Marco Scutaro hit a sacrifice fly in the third after Jacoby Ellsbury's triple, and Gonzalez homered into the Red Sox bullpen for a 4-2 lead in the sixth.

In the sixth, Varitek held on and tagged out Lawrie, who came crashing in with his forearms while trying to score from third on Adam Loewen's bouncer to second with the infield in, Varitek flipped over backward.