OAKLAND -- Tony Kemp was already resigned to feeling that he was the main reason the A’s were about to lose a heartbreaker in extra innings for the second straight night.

Up until the 12th inning of Saturday’s 7-6 victory over the Red Sox, Kemp was having what he described as the “worst game of my big league career.” Nothing seemed to go right, from his error in the fourth that led to Boston scoring two runs shortly after to his bobbling of a potential double-play ball in the fifth that led to another run.

Things only got worse as the game went into extras. At the plate with a golden opportunity in the 10th as the A’s had the bases loaded and no outs in a tie game, Kemp attempted a bunt, which he said was the result of a miscommunication with A’s coaches, that was popped in the air and caught by Red Sox reliever Brandon Workman. One batter later, Elvis Andrus hit a hard liner to left that ended up an inning-ending double play.

Sometimes, though, the baseball gods come back around to offer an opportunity at redemption. Kemp got his chance, and he seized it.

Entering the bottom of the 12th trailing by two runs, the A’s stormed back to tie the game on back-to-back RBI hits from Seth Brown and Jed Lowrie. The stage was set for Kemp to erase his frustrations. With one swing, he did just that, driving a pitch from Matt Andriese deep enough to score Brown from third for a sacrifice fly that secured Oakland a walk-off victory.

“He wanted to [redeem himself] badly,” A’s manager Bob Melvin said of Kemp. “He’s done such good work for us this year. He ends up getting the biggest at-bat of the game.

“You gotta fight through some demons when you don’t get off to a good start. When something like that happens and you end up coming up with the last at-bat, that’s good stuff.”

Kemp’s face as he watched Brown cross home plate was a perfect description for what transpired over Saturday’s nearly 4 1/2-hour marathon. There was no emotion. The usually energetic Kemp could only lift his arms up in the air and tilt his head up to the sky with a look of relief before his teammates made their way over to mob him near first base.

“When you’re out there, you just want to make every play,” Kemp said. “Obviously, the walk-off makes it better. I’m not trying to be down on all the negatives, but there’s still a lot of emotions running through me that I can’t really explain.

“Seeing runs cross home plate that you were a part of giving up is a hard pill to swallow, especially in a big series like this. To be able to end on a positive is good.”

In the midst of a rough stretch in which they had entered the day having lost eight of their previous 12 games, the A’s knew they were going to have to show an unrelenting will. Against the team that came into the day with the best record in baseball, they dug deep.

A recently maligned bullpen stepped up big. Firing zero after zero to keep Boston off the scoreboard after the seventh in relief of starter Cole Irvin, A’s relievers held the Red Sox offense -- a squad that was riding an eight-game winning streak in which it averaged 6.9 runs per game -- scoreless for four consecutive innings. J.B. Wendelken had the only hiccup, giving up two runs in the top of the 12th. But the A’s offense came to life at just the right moment in the bottom half, ending it on Kemp’s sac fly.

“It was about as entertaining as a game could be except for everybody playing in it,” Melvin said. “The two runs they scored in that inning felt like 10 based on the way the game was going. To come back after feeling like we had it in our grasp a couple of times earlier showed some mettle.”

It was a win that was difficult for anyone to put into words, given the many twists and turns that took place. Melvin, usually one to expand with great insight after such big wins, struggled to comprehend what had just taken place.

“I’m fried right now. It was a crazy game,” Melvin said. “That’s about as much as I can give you at this point. Tomorrow morning, maybe I’ll come up with a different adjective.

“It was the most spirited game of the year. I’ll put it that way.”