United head to the LNER Stadium on Saturday knowing they will need to make it four straight away wins if they are to book their place in the National League.
Victory at Farsley Celtic saw Paul Cox's side sneak into the top seven on the final day of the regular season, before knockout victories at Kidderminster Harriers and AFC Fylde.
"That shows the fighting spirit we have," Byrne said.
"Since we knew the play-offs were back in our hands we've been in a different gear really.
"Farsley, Kiddy and Fylde, we've just wanted it more. It's a very, very happy dressing room."
Facing the Minstermen in the weekend's promotion final didn't seem probably up until a fortnight ago as Boston struggled to find rhythm and consistency.
But Byrne - who joined the club from Brackley Town this summer - never lost faith.
"I understand the quality we have in this changing room," he added.
"I knew what I was leaving at Brackley and it was a very tough decision, having been there five years.
"I wanted to take that next step and that can happen on Saturday. It's down to us really.
"I've been at every stage at this play-offs and lost at every stage.
"But for this club to get back to the National League, at least where it belongs, we know we have to perform as we have done in recent games and take everything into it."
Boston have sold out their allocation of 878 seats for Saturday's final.
Despite it being a larger figure than the number of fans who travelled to the past three away games, the amber and black section will feel much smaller in a crowd of 7,500.
However, the connection between terrace and pitch has blossomed in recent weeks and Byrne is aiming to have one final celebration with the United support this campaign.
"The fans are absolutely amazing and we appreciate how much time, money and effort it takes to support us," the Irishman said.
"I'm glad we've given them things to go home happy with and I hope we can do it again Saturday."
Bodies will have to be put on the line once more if Boston are to succeed.
Byrne - who has missed games through losing three teeth, standing on a nail and catching Covid this campaign - knows all about that after taking a Nick Haughton free kick direct to the face on Sunday.
After pulling himself to his feet, Byrne played on to help United defeat Fylde.
"Nick's got a terrific strike on him so I'm happy it hit me," he said.
"If I have to take one in the face for the team then that's fine."
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