Red Sox catcher Jason Varitek watches the flight of his three-run homer in the fourth inning of yesterday’s series finale against the Texas Rangers.

AP / LM Otero LM Otero

ARLINGTON, Texas — It won’t always be like this, because no team, no matter how good it is, can have this kind of run for an entire season.

But for now, the Red Sox can seemingly do no wrong and they’re wisely making the most of it.

As the Sox finished up their sweep of the hapless Texas Rangers here yesterday with a 6-5 victory, a familiar plot played itself out. Trailing, 4-3, after seven innings, the Sox scored two runs in the eighth and one more in the ninth.

In all three wins here, the Sox had to come from behind after the fifth inning. Yesterday’s win was their fifth this season in which they trailed after seven innings.

Not much deters them. Yesterday, they were without their best hitter (David Ortiz) and their best reliever (Jonathan Papelbon), and it didn’t matter.

Yesterday’s win was started by their fifth starter and finished by the alternative closer. Still, it didn’t matter.

“This was huge for us,” said starter Julian Tavarez, “but it doesn’t surprise me.”

Nor should it. Not the way the Red Sox are going.

The Sox now lead their closest pursuers — the Baltimore Orioles — by a gaudy 11½ games and have won 15 of their last 20 and 22 of their last 30. Not even a change of venue slows the Sox away from home — they’ve won eight of their last 10 and 10 of their last 14. Since dropping four of their first seven on the road, the Sox have cleaned up, going 15-4.

The winning pitcher was Joel Pineiro, who picked up his first victory of the season with 1 2/3 innings of perfect relief, making his first appearance since Wednesday.

“We pick each other up in the bullpen and push each other,” said Pineiro, who retired all five hitters he faced, three by strikeout.

The tying run was produced by slumping outfielder J.D. Drew, who only two at-bats earlier had snapped an 0-for-17 skid. In the eighth, he slapped a single to right, scoring Kevin Youkilis.

“That’s why we got him,” said manager Terry Francona of Drew. “I know he’s been struggling, but he came through when we needed him. And we need him to hit.”

The winning run came from Dustin Pedroia, who crunched his second homer of the season in an epic battle with Rangers closer Eric Gagne, finally rocketing a ball out to left on the 12th pitch.

“I knew it was going to be a fight,” he said of the at-bat. “I finally got a good pitch to hit and hit it well. I saw a lot of pitches, so that helped me out.”

Finally, the save went to Hideki Okajima, who filled in for Papelbon, who had pitched in the first two games of the series. Okajima had some anxious moments, yielding a run-scoring single to Mark Teixeira, which put the potential tying run on base.

But Okajima got Sammy Sosa to fly to center for the final out, capping the Sox’ first three-game sweep here since 1973.

Tavarez cruised through the first five innings, allowing a leadoff single to Kenny Lofton, the first batter he faced, before retiring 15 of the next 17 hitters.

But Tavarez unexpectedly came unglued in the sixth. He walked Lofton, yielded a single to Michael Young, then was tagged for a mammoth 450-foot homer into the upper deck by Teixeira, wiping out the Sox’ 3-0 lead.

Tavarez had shaken off catcher Jason Varitek, but made the mistake of hanging a slider over the middle of the plate.

“You hang one and it cost me the game,” said Tavarez. “That was the difference. But the bullpen came through after I dropped the game.”

Tavarez, who was so efficient through the first five, left a mess — first-and-second, two outs — for J.C. Romero. But Romero got Ramon Vazquez on an inning-ending groundout before slipping into his own trouble in the seventh.

He yielded a leadoff double to Lofton and a one-out walk to Teixeira. Pineiro came on to face Sosa, hoping for either a double play or a strikeout. He got the latter, catching Sosa looking at a called third strike.

Then came the defensive play of the game, with Coco Crisp turning in a brilliant, sprawling catch to save two runs.

“When I saw that ball hit,” said Pinerio, “nobody was close to the ball. That was just a great catch.”

Varitek had staked the Sox to a 3-0 lead in the fourth with a three-run belt off starter Kameron Loe, his first homer since May 8.

smcadam@projo.com