For months, the Red Sox lineup had a giant dead spot. The bottom third of the batting order seemed like the place where rallies withered.

Through much of the first four months of this season, the heavy lifting was left to the top of the batting order. Thanks to the lengthy struggles of catcher Jason Varitek, centerfielder Coco Crisp and shortstop Julio Lugo, a group that was joined in the summer by outfielder Jacoby Ellsbury, Boston’s offense seemed to sag with a lengthy list of non-contributors.

Yesterday’s 5-4 win over the Orioles underscored a dramatic reversal that has taken place in recent weeks. The top six spots in the Red Sox lineup reached base just six times while going 4-for-25, with three of those hits coming from Dustin Pedroia.

Yet with the top of the lineup stalling, the Sox still managed to produce and sustain rallies thanks to key contributions from previously unlikely sources. It was Jason Varitek (0-for-3 with a walk), Alex Cora (3-for-4 with the game-winning run) and Coco Crisp (2-for-3 with a pair of infield hits and a bases-loaded walk) who created pressure on the Baltimore pitching staff.

The formula has been increasingly common. Despite a shifting cast of characters due to a succession of recent injuries, the Sox have managed in recent weeks to create devastating top-to-bottom lineup pressure on their opponents, denying pitchers the chance to come up for air.

“We seem to be getting contributions all over the place,” said manager Terry Francona. “That’s a good way to win.”

Since August 16, the Sox are getting staggering production from the bottom third of their lineup. The seventh through ninth spots in the order have combined to hit .333 with a .411 OBP and .484 slugging mark in those 17 games. Those numbers roughly match what Dustin Pedroia (.333/.378/.505) has done over the course of the season.

The process has been perhaps even more impressive than the results. A revolving door of players—Varitek, Crisp, Alex Cora, Kevin Cash, Jeff Bailey, Jed Lowrie and Sean Casey—has slotted into the bottom third of the lineup. Yet the production has not diminished, as the Sox have featured their most complete lineup of the season.

“It’s been pretty similar to the (2007) playoffs, where every guy in the lineup is grinding out at-bats,” said Sox hitting coach Dave Magadan. “It seems like every guy is seeing four, five, six pitches an at-bat.”

“When guys at the bottom are getting on base, you can’t pitch around (the middle of the order hitters). You have to go after them. That’s what it creates. When your pitchers are having to labor one-through in the order, I like our chances.”

The Sox have benefited from a number of players getting hot in lockstep. Varitek, who walked as part of a two-run rally in the seventh, is now hitting .320 in his last 14 contests, and has shown signs of making consistent, hard contact. Since he commenced his current hot streak on August 16, the Sox are averaging exactly six runs a game.

Crisp dismissed yesterday’s two-hit effort as “lucky”, particularly the ninth-inning bunt up the first-base line that went foul before hitting a rock and kicking back into fair territory for a single. Even so, he is hitting .457 (16-for-35) in his last nine games.

Cora, likewise, is hitting .417 in his past six games. Yesterday, he was a crucial presence in the lineup and in the field. He made a key defensive play, gunning down Aubrey Huff at third base on a fielder’s choice grounder with none out in the eighth.

Yet his defensive acumen is considered something of a given. His offense, on the other hand, proved a huge boost for his club yesterday, as Cora went 3-for-4 and scored the game-winning run.

The development underscored the recent transformation of a weakness into a strength, something that has helped the Sox to achieve their most sustained success of the season.

“You have three or four guys hot at the same time hitting at the bottom of the order. It’s been a good formula,” said G.M. Theo Epstein. “Overall, our offense has been succeeding because we’ve had a solid, disciplined approach, one through nine. That’s what ultimately wins baseball games.”

Alex Speier is a Senior Writer for WEEI.com.