Back-up catcher Jose Lobaton kept Tampa Bay's season alive with a walk-off home run in the ninth inning that lifted the Rays to a 5-4 win over the Boston Red Sox in Game 3 of their American League Division Series.

Trailing 2-0 in the best-of-five series, the writing was on the wall for the Rays after they fell behind 3-0 early in the must-win encounter and then blew a 4-3 lead in the top of the ninth.

However, Lobaton smacked a two-out blast off Koji Uehara to give the Rays the win and cut the series deficit to 2-1.

"It's unbelievable. It's something you can't explain," Lobaton said after coming off the bench in the ninth.

"We never give up. We're going to keep fighting."

The Rays are used to being on the brink and fighting their way out of it, having now won an elimination game for the fourth time in nine days.

Tampa defeated Toronto in a must-win regular season finale, then beat Texas in a one-game tiebreaker and Cleveland in the wild-card playoff.

Outplayed twice at Fenway Park, the Rays finally looked to be a match for Boston when Evan Longoria smacked a game-tying, three-run homer in the fifth inning before Delmon Young brought in the go-ahead run on a groundout in the eighth.

The joy appeared short-lived, however, when Rays reliever Fernando Rodney blew the lead in the top of the ninth to allow Boston to tie the game 4-4, but Tampa Bay fans were soon back on their feet in the bottom of the inning.

"That was a moment to remember," Longoria said of his teammate's home run.

"Lobaton came through when we needed it and now we can hopefully carry that momentum into (Game 4)."

Boston won the first two games by a combined score of 19-6 and the Red Sox dominated early in Game 3, scoring once in the first and twice in the fifth, which was the final inning completed by Tampa Bay starter Alex Cobb.

The Red Sox had Clay Buchholz on the mound, who was limited to 16 starts during the regular season because of a neck strain that sidelined him from June to September.