Boston’s Jacoby Ellsbury reaches first safely last night in the eighth inning on a swinging bunt that scores Jed Lowrie from third and gives the Red Sox a 6-5 lead.

The Providence Journal / Bob Breidenbach

BOSTON –– A swinging bunt trickles down the first base line. A pitcher stumbles in pursuit. The winning run crosses the plate.

And in a matter of seconds, the complexion of a playoff race changes.

So it was at Fenway Park last night, where the Red Sox claimed an improbable 7-5 comeback win over the Toronto Blue Jays, themselves still entertaining playoff hopes, however slim.

For much of last night, it seemed as if the Red Sox were dangerously close to eliminating themselves from repeating as American League East champions.

The Sox were blown out in the opener of their day-night doubleheader against the Blue Jays, throttled 8-1. Meanwhile, the plucky Tampa Bay Rays beat the Yankees in the first game of their own day-night doubleheader.

Another Red Sox loss and another Tampa win would have set the Sox five games behind in the loss column.

Sure enough, the Sox fell behind early and the Rays were heading for a sweep at Yankee Stadium.

That likely would have been too much ground to make up over the final 14 games. True, the Sox have three games remaining with the Rays, beginning tomorrow night at Tropicana Field.

But since a sweep is highly improbable –– the Sox are winless there in six tries this season –– the most the Sox could have hoped to make up is a game in the standings. That would have left just 10 games for them to make up the rest of the deficit.

Then, things began to change. In the Bronx, the Yankees tied, then went ahead of the Rays. Minutes later, Jacoby Ellsbury’s roller remained inches fair as Scott Downs inadvertently planted himself on the grass in an effort to field it and Jed Lowrie scored from third, clapping his hands madly upon arrival to home.

A wall-scraping double from David Ortiz then gave Jonathan Papelbon some additional room for error, not that he needed it –– Papelbon retired the Blue Jays in order and the Sox escaped with a 7-5 triumph.

“That,” offered Jason Bay, “was a huge win.”

“Without a doubt,” echoed Kevin Cash. “We lose and we’re four back (in the standings). Instead, we win and we’re just two out. That’s a big swing right there, especially with the way (the Rays) are playing.”

Earlier in the week, the Sox had nearly allowed the division title to slip through their hands.

Things turned Tuesday night in the ninth inning, when, after Bay’s homer the inning before, the Sox were three outs away from beating the Rays for the second time in as many nights.

Instead, the resilient Rays bounced back and scored three times against Papelbon.

It was all downhill from there. The next night, the Sox stranded the potential winning in scoring position four straight innings in a row. Finally, in the 14th, the Carlos Pena clubbed a three-run homer to send the Rays to a victory.

Instead of leaving town a half-game out of first, their confidence shattered, the Rays were emboldened and their lead in the division had actually grown.

That left the Sox having to make up ground this weekend. The Sox didn’t do that yesterday, splitting a day-nighter while the Rays did the same. But just as critically, they didn’t lose ground, either.

“It buys us a little more time,” said Cash. “It means we still have a chance.”

It’s not as though the wild card is a death sentence for aspiring teams. Indeed, wild card entrants won three straight World Series from 2002-2004 (Angels in 2002; Marlins in 2003 and Red Sox in 2004).

What’s more, the last three World Series have featured wild card teams –– the 2005 Houston Astros, the 2006 Detroit Tigers and 2007 Colorado Rockies.

But the assignment is not without its challenges.

Should the Sox qualify as the wild card this time, they would probably open the ALDS at Anaheim. The Sox have swept the Angels in the last two post-season meetings –– the ALDS in both 2004 and 2007 –– but this season, the Angels have dominated the Sox, both at home and at Fenway.

The Sox were swept in Anaheim in their only visit this season and the Angels won 5-of-6 in Boston. For the season, the Angels hold an 8-1 edge.

As a wild-card, the Sox wouldn’t enjoy home field advantage unless they reached the World Series when they would enjoy home field by virtue of the American League’s victory in July’s All-Star Game.

A second-round ALCS matchup with Tampa, Chicago or Minnesota would also involve opening on the road. And, it should be noted, unless the Sox go undefeated on their upcoming six-game road trip to Tampa and Toronto, they won’t finish over .500 away from home during the regular season.

Since their epic comeback against the Yankees in the 2004 ALCS, the Sox are 9-2 at Fenway in the post-season and there’s little doubt that the raucous environment at Fenway helped fuel the team’s come-from-behind victory over Cleveland in last October’s ALCS.

Two weeks are left. Seeding and opponents are still up for grabs.

The Sox don’t know if they’ll be division champs yet. But after last night, here’s what they do know: they still can be.

smcadam@projo.com