BOSTON -- The Blue Jays aren't ready to concede -- not until algebra is no longer on their side. That isn't to say that Sunday's 4-3 loss to the Red Sox didn't deal a devastating blow to Toronto's flickering postseason aspirations.

The Blue Jays arrived at Fenway Park for this four-game weekend series in Boston with an opportunity to gain some serious ground in the American League Wild Card race. Toronto needed three or four wins and instead came away with just one, thanks in part to a bevy of close calls and bad breaks.

Not even Blue Jays ace Roy Halladay -- on the mound when Toronto's 10-game winning streak came to a close earlier in the week -- could salvage the crucial series during the finale in the Fens. Halladay did his part, though, turning in a strong effort that simply wouldn't hold up in light of the Blue Jays' quiet showing at the plate.

"It was a big series for us," Halladay said. "Knowing we were back a ways, we had to come in and win more games than we did. There's obviously still two weeks left to go, but it's tough to come in, knowing you've got to win three or four and getting one. It was a tough series."

Now, Toronto is hoping for help from a few other clubs. With just 12 games left on their regular-season schedule, the Blue Jays' chances of erasing the gap between them and the Red Sox in the Wild Card standings -- an 8 1/2-game deficit with the loss -- are dangerously thin.

To stay alive, the Blue Jays need another long winning streak, combined with some missteps by the Red Sox and Twins (currently second in the Wild Card standings) to slip up down the stretch. Otherwise, Toronto's focus will quickly turn to next season -- a mind-set the players aren't ready to accept.

"We need a lot of help from other teams," Blue Jays first baseman Lyle Overbay said. "You don't really want to put it on other teams to help you out -- you want to do it yourself. We're doing something that, hopefully, we can kind of continue and maybe even take it over to next year, knowing that we can do it. It's just a matter of kind of getting on a roll."

Toronto was on a roll before it arrived in Boston, winning 11 games in a 12-game span. That stretch briefly pulled the Jays back into the playoff discussion, though the Red Sox effectively damaged Toronto's hopes. In the finale, Boston left-hander Jon Lester spun eight strong innings to quiet the Jays.

Following a first-inning solo home run from Toronto's Jose Bautista, Lester settled in and shut the Blue Jays down. That gave the Red Sox time to string together a handful of runs against Halladay, who wound up with yet another hard-luck loss. A run-scoring grounder in the first and an RBI single in the second put Toronto behind, 2-1.

"Doc, once again, gave us a chance to win," Blue Jays manager Cito Gaston said.

Halladay exited after seven innings and was charged with three runs -- two earned. The unearned run came courtesy of an RBI single by Boston's Coco Crisp in the seventh inning, shortly after a rare fielding error from Overbay at first base. That was only one of the few bad breaks that cost the Jays.

In the second, Gregg Zaun was called out at first base after he appeared to beat a throw from second baseman Dustin Pedroia. In the seventh, following Overbay's error, Marco Scutaro was playing the left-handed-hitting Alex Cora to pull, preventing the Jays' second baseman from hustling to second in time to turn a would-be inning-ending double play.

In the eighth inning, right fielder Alex Rios couldn't come up with a difficult shoestring catch on a line drive from David Ortiz, allowing the slugger to pick up a rare triple as the ball rolled to the wall. Ortiz then scored on a sacrifice fly from Kevin Youkilis to put the Blue Jays behind, 4-1.

"We just didn't get our breaks and we didn't take advantage of that stuff," Overbay said. "It hasn't been like we've been playing. We've been playing a lot better than that. It's frustrating, because I think we could've done what we wanted to do."

There was also a questionable ruling by second-base umpire Doug Eddings during a late rally by the Blue Jays in the ninth inning. After Adam Lind had already plated Vernon Wells with an RBI single, Overbay sliced a pitch from Boston closer Jonathan Papelbon into the left-center field gap.

Overbay attempted to move to second base for a double, and his left hand appeared to touch the bag before he was tagged out by Pedroia. Instead, Overbay threw his arms in the air in disgust after being called out. Two groundouts and one run later, Papelbon notched his 38th save and Toronto picked up its third loss in four games.

"If a couple of calls go our way, we're still playing," Gaston said. "That's what's disappointing. As far as the way the guys played, I'm not disappointed at all. They never gave up. They kept battling."

And they'll keep hoping.

"There's always something to play for," Halladay said. "I think it's important for us to finish strong -- it's important for us to continue to play. This can't be the end all, be all series. We have two weeks left and I don't think there's anybody in here who's going to quit."