JJ O’Donnell headed the Heed in front early on before two penalties from Jordan Thewlis put the host’s 2-1 up at the break.
Alex Nicholson made it 2-2 from the spot before a Jake Wright brace and another from Jay Rollins saw Boston through to the play-off final despite a late consolation from Elliot Forbes.
Scroll down and click through the pages to see Dominic Scurr’s Gateshead player ratings from the match:
1. Brad James - 5
Couldn't do much about any of the five goals conceded but will be very disappointed to have let in so many after his penalty heroics last weekend. Photo: Charlie Waugh
2. JJ O'Donnell - 7
In action at both ends with some good blocks and did well to glance in his ninth of the season to give Gateshead the lead. Photo: David Rogers
3. Jake Cooper - 4
Looked panicked in possession and gave the ball away in the build-up to the crucial third goal for Boston. Booked. Photo: David Rogers
4. Mike Williamson - 5
Conceded the penalty but appeared to be harshly penalised after appearing to pull out of the challenge. Booked in the aftermath of the second penalty. Photo: Emilio Andres Leal Kirtley