Sox right fielder Mark Kotsay (without cap) celebrates yesterday’s victory with his teammates. Kotsay contributed a game-tying, two-run triple.

The Providence Journal / Bob Breidenbach

BOSTON — With all of the talk about the Red Sox’ offensive onslaught during this homestand, it seems like the club’s defense has been somewhat overlooked.

Yesterday, in particular, Boston’s solid, heads-up and fundamental play in the field helped the team to a dramatic, come-from-behind 5-4 victory over the Orioles at Fenway Park. Boston scored five runs in the last three innings to erase a 4-0 deficit and sweep Baltimore in the three-game series.

Offensively, the Red Sox played small ball in the bottom of the ninth inning for the walk-off win. Alex Cora, who led off with a single, reached second on a bunt base hit by Coco Crisp. Jacoby Ellsbury dropped down a sacrifice bunt in an attempt to move the runner to third, and when Orioles pitcher Jim Miller attempted to get the lead runner, he threw the ball into left field, allowing Cora to score.

“We won a game that was losable,” said Red Sox manager Terry Francona, “and we’ll take every win we can get.”

While Cora’s leadoff single in the ninth and his game-winning run were crucial, his defense in the top of the eighth inning may have been just as important. Baltimore the eighth with a two-run lead. The Orioles’ Aubrey Huff led off with a single, stole second and was poised to add some insurance on Oscar Salazar’s grounder to the left side of the infield.

Huff was going on contact when Cora quickly snared the grounder behind the runner and made a quick throw to third baseman Jed Lowrie for the out.

“You don’t make that play unless you’re already making it before the ball is in your glove,” Francona said. “You don’t see that play too often, and it was a game-saver.”

Cora and Lowrie reacted quickly on the play, knowing that if the Orioles were able to increase their lead, a comeback attempt by Boston could fall short. But that wasn’t the case.

“I just took a gamble,” said Cora. “The way the game was going, if they score one more run, it would have been tough for us to come back. I felt Aubrey would have a good lead (at second), so I took a chance and Jed made a great play. That throw was coming at (Huff’s) helmet, Jed got the tag down and it changed the momentum of the game.”

It wasn’t the only important defensive play in the inning.

With Salazar still on first, Baltimore’s Luke Scott smoked a grounder down the line that was grabbed by Sox first baseman Mark Kotsay. He stepped on the bag for the out and made the throw to Lowrie to double up Scott, ending the inning and the threat.

What made Kotsay’s play even more impressive was the fact that he hasn’t played first base since Sept. 2, 2006, while a member of the Athletics. Normally an outfielder, the Sox newcomer was asked to play the corner spot because Kevin Youkilis was out of the lineup because of a stiff back.

“I thought I handled first base OK,” Kotsay said. “I didn’t embarrass myself. Any chance you get to play, you need to take advantage of it.”

Kotsay came through at the plate, too. His two-run triple in the bottom of the eighth tied the score at 4-4.

Cora and Kotsay made two of the biggest plays of the game, proving that the bench players can handle the job when put into the mix.

“We’ve been playing very good defense,” said outfielder Jacoby Ellsbury, who robbed Huff of a possible home run with a leaping grab over the right-field wall in the top of the fifth. “Guys are running things down in the outfield. That play A.C. and Jed made to get Huff at third base was a tremendous play. Everyone has been playing well.”

Dustin Pedroia continued his offensive surge. He hit his second home run in as many games and went 3-for-4, including a single and a double. He now has recorded multiple hits in 56 games this season and leads the American League in that category, and his 22 three-hit performances also is the most in the majors.

While Pedroia’s play is no surprise, getting contributions from Cora, both in the field and at the plate, has been a bonus.

“We’re pretty fortunate right now,” said Francona. “He’s impacted the game in a huge way today.”

jmcdonal@projo.com