"It was really close, right on the edge," said Red Sox catcher Kelly Shoppach. "I thought it could have went either way, and then the 3-2 was just a mislocated fastball."
With the count full, Mauer got a fastball that caught a little too much plate and he crushed it to the opposite field for a game-breaking blow.
"It's a tough one," said Red Sox third baseman Nick Punto. "He put a nice swing on it. That's why he's one of the best players in the game."
The only way Aceves could look at his misfire is that he is human, just like Rackley is.
"I thought it was a strike," Aceves said of his 2-2 offering. "That's in the past. I've got nothing to say to that. Why don't you ask the umpire how he missed the pitch before? Ask him. It's part of the game, mistakes. And also I make a mistake the next pitch and that's it. It cost us the game."
This type of loss would be a dagger to the heart on any night. But when you consider the point of the season it came at for the Red Sox, it felt doubly crushing.
At a time the 53-55 Red Sox are scratching and clawing to remain in contention for the postseason, they've lost four in a row -- three against the 47-60 Twins.
That's why this one probably stings more than when Boston blew a 9-0 lead to the Yankees back on April 21.
The Red Sox have 55 games left in the season and trail the Yankees by 10 games in the American League East and are five games off the pace in the Wild Card standings.
"They're all devastating now," said Punto. "You get this late in the season and you look in the standings and we're not really sitting in a great position in the Wild Card. There are a lot of teams. We really can't afford to lose games like that. [Clay] Buchholz was outstanding tonight, and this offense is too good to score that few runs."
Punto was part of the 2011 Cardinals, who had an in-season turnaround for the ages and then won the World Series.
"We were a mediocre team in St. Louis. We were mediocre until September. Then we went on a really nice run, got some help from Atlanta, and somehow came back from a 9 1/2-game deficit," Punto said. "The similarities here are very similar. We're very mediocre. We're not playing good baseball. We have the talent in this room to do it. We just haven't. We know we need to go on this run. The clock's ticking. We just need to play good baseball."
That quest starts again Sunday afternoon, when the Sox will try to stave off a four-game sweep against Minnesota.
"It's a nice day game," manager Bobby Valentine said. "We'll bounce back -- unless they're going to call off the season. If they allow us to play, we'll be out there playing hard. We've got to put together a nice little run. This is a lousy one, a lousy game to lose, but we had to come back to get the lead. Maybe we'll get the lead and keep the lead. Who knows?"
As Valentine alluded to, before things fell apart on Saturday, Boston had just gone ahead in the bottom of the eighth, riding a pinch-hit homer by Pedro Ciriaco and an RBI single from Cody Ross to a 4-2 lead.
It was the first home run of Ciriaco's career, and the third time in the last week he's provided a key hit to put the Red Sox ahead in the late innings. With chants of "Pedro, Pedro, Pedro," Ciriaco came out for a curtain call.
By the time the game ended, his moment was only a footnote.
"It was pretty good, but the only matter is to win the game and we didn't win the game tonight, so we just have to move on and look forward to tomorrow," Ciriaco said. "He gave me a good pitch and I put a good swing."
Unfortunately for the Red Sox, momentum had not stopped swinging in this one.
Aceves, who had minimized the damage when he entered a bases-loaded, nobody-out jam in the eighth, didn't have it in the ninth.
Alexei Casilla ignited the winning rally for Minnesota with a one-out double. Jamey Carroll lined a single to center to drive in Casilla, making it a one-run game.
When Aceves got Denard Span on a flyout, Boston was just one out away from snapping a three-game losing streak.
But Ben Revere's single up the middle kept hope alive for the Twins. After a wild pitch by Aceves moved the runners up, Mauer worked the count in his favor and then did his thing.
"He's got some good movement on his pitches and I was just trying to stay short and not do too much," said Mauer.
Before the late-inning chaos, Clay Buchholz put Boston in position to win, pitching seven strong innings in which he scattered seven hits and allowed just one run, which wasn't earned. The righty walked one and struck out three and had a 2-1 lead when he exited.
Over Buchholz's last four starts, he is 1-0 with a 1.20 ERA.
"I mean, it's not about me getting the win -- it's about the team win," said Buchholz. "Things happen where one-run leads, they just don't hold up all the time. For our offense to bounce back and score two, that put us in a good spot. This game is humbling because things can happen like that. Just one pitch that you leave up or not exactly where you want it, and it can end up out of the yard and that's what happened."
Andrew Miller, who has typically been reliable for the Sox this season, came on in the eighth. He gave up a walk to Span, an infield hit to Revere and a walk to Mauer to load the bases with nobody out.
That put Aceves in a tough spot. The righty gave up a game-tying sacrifice fly to Justin Morneau, the first batter he faced. But otherwise, he got through unscathed.
"We had one great job by Aceves in the eighth and then leakage in the ninth," Valentine said. "Andrew Miller has just been terrific against left-handers, just flying open a little too much tonight, couldn't get in the strike zone."
Shoppach, who was also part of a surreal pennant race comeback last season with Tampa Bay, is confident that the Red Sox will stay together in the face of adversity instead of fall apart.
"I think that's the makeup of the guys," Shoppach said. "Guys like being around one another, enjoy coming to the park, spending time with each other. When you have that kind of chemistry among players, it makes it fun to come to the yard. You turn the page and move on pretty quick."
The Red Sox have left themselves no choice.