The Bills quarterback threw two interceptions and saw a fumble recovered for a touchdown in a nervy encounter, having entered the game with just one playoff interception in 228 passing attempts.
Those turnovers allowed the Dolphins to build up steam, fighting back from a 17-point first-half deficit and then taking an early second half lead, with Allen acknowledging his mistakes after the game.
"At half time, we were just talking to ourselves, just settling down, trying to refocus," he told reporters. "The turnovers hurt us, we really let them back in the game.
"We were up 17-0 with chances and I gave them the ball two times, gave them a touchdown, they're things you can't do and you can't expect to win like that, so there's some stuff to clean up."
The Bills defense did their part though, intercepting rookie quarterback Skylar Thompson twice and making big stops to halt the Dolphins' recovery, and Allen vowed to be better for them in future games.
"Turnover margin, especially in the playoffs, is so big. It really helps us out and bails us out," he added.
"I can't praise our defense enough for playing the way they did. I put them in some tough situations today, so I've got to be better for them."
It was not just the defense who played their part in frustrating the Dolphins offense, however, with the atmosphere in Buffalo leading to errors – including a delay of game penalty that pushed Thompson's offense back to six yards instead of one in fourth down of their final drive.
"We're going to need the Bills mafia in the building being load and disruptive, I thought they did a good job tonight causing a couple false starts and delay of games, that is such a huge momentum shift for us," he said.
"When it's fourth and one, you cause a delay, then it's fourth and six, which changes the complexity of that call, so shout out to our fans."