The Chairboys enjoyed a great escape inside 30 seconds. With home defender Roger Johnson struggling, United's Chris Holland watched as his goalbound lob was hooked to safety by Mike Williamson.
A difficult cross from home full0back Clint Easton gifted Tommy Mooney an opportunity on nine minutes, but the experienced striker failed to connect at the far post.
Desperate to improve, Wycombe pushed forward defender Danny Senda. He delivered a cross that striker Charlie Griffin met perfectly with a forceful header.
The ball though dropped into the grateful arms of the Boston keeper Michels Kuipers.
Suddenly the formbook was turned upside down as Boston dramatically took the lead thanks to midfielder Francis Green.
Lunging Wycombe tackles failed to rattle the former Peterborough player and Green smoothly ran on to place a glorious shot past the stranded Frank Talia.
Wycombe immediately stepped up the pace with strikes from Mooney and midfielder Joe Burnell giving hope to the home support.
On-loan keeper Kuipers again denied them an equaliser, this time Mooney being the frustrated player. The big Dutch stopper then swooped to his right to hold a well hit Matt Bloomfield drive.
During the added on time at the end of the first half, referee Mr Door, who had already shown his yellow card to Wycombe's Kevin Betsy and scorer Green, produced a second yellow for Boston captain Stewart Talbot for a rash tackle on Burnell.
Mooney, always the most likely to open up a resolute visitors backline, stood frustrated as Kuipers held under the crossbar.
The Boston keeper, who at times appeared to be the only person trying to stop Wycombe, producing a point-blank save to stop Griffin from converting Senda's cross.
Senda hit the Boston crossbar on 67 minutes, but eventually came the leveller thanks to Bloomfield.