The success in extras hasn't just become a cute little stat, but a legitimate difference-maker in the standings.
The 86-64 Sox lead the Yankees by the three games with 12 to go. In other words, if manager John Farrell's team was 10-7 in extras, they'd be trailing in the division. Boston is first in the Majors in extra-inning wins this season.
"It's probably one of the main reasons we sit here [in first place] today," said Farrell." And that goes to the depth of the bullpen and how well they've pitched."
What does that record in extras say about the 2017 Red Sox?
"That no matter how late it is or how deep in the game we are, we're going to continue to plug away," said center fielder Jackie Bradley Jr.
On Friday night, the Sox trailed the Rays, 5-2, in the ninth before tying it up and winning, 13-6, in 15 innings at Tropicana Field.
Monday's game included another comeback story, but a much different type. A tough start by Doug Fister pinned the Red Sox into a 6-1 hole through four innings.
Instead of chipping away methodically, Boston erupted for six runs in the fifth to take the lead. To mount rallies like that, you need nine-pitch at-bats like the one Bradley had en route to an RBI single that sliced the deficit to 6-2 and set the stage for the go-ahead three-run double by Mookie Betts later in the inning.
"It was one of my best at-bats," said Bradley. "I was just competing. At that point, you stop trying to worry about scouting reports and what is he going to do. I'm just up there competing. I want to beat you. That's my goal."
But the tenacious at-bat by Bradley and the bases-clearing knock by Betts were made possible by a bullpen that plugged nine innings of two-run relief after Fister's exit.
Capitalizing on the expanded roster, Farrell was able to deploy nine relievers.
Addison Reed got out of a first-and-third, one-out jam in the eighth to keep the game tied. Carson Smith picked up his first save since undergoing Tommy John surgery.
"Honestly, we don't need games like this to give us confidence," said Reed. "Every single one of us in that bullpen is extremely confident in ourselves and each other. We know what we can do, and I think we're showing it."
When the games start to evolve into marathons, the Red Sox can't help but feel they have the other team right where they want them.
"There is some level of comfort. I can't say you're always feeling great about the situation, particularly on the road, but the number of games we've played and how we've executed late in games, I'm extremely proud of the way they go about it," said Farrell. "And our guys on the mound, they continue to make quality pitches. And it takes a combination of those two things."
For the Red Sox to prevail Monday, they needed someone to get the big hit. Andrew Benintendi provided it, drilling a single through the second-base hole and into right with two outs in the 11th.
Seldom-used Tzu-Wei Lin set it up with a 3-2, two-out walk.
"We're kind of used to these extra games now, so we know what it takes," said Benintendi.
"It just shows the tenacity and the grit of this team," said Bradley. "Down early, but still plenty of game to play."