A sublime free-kick from Jason McCarthy earned Wycombe a vital three points in their survival bid and nudged his old club Walsall towards the drop.
McCarthy got the ball up and down from close range to score the only goal of the match just before the hour mark.
Victory moves Wycombe four points above the relegation zone, with Walsall four adrift of safety with two games remaining.
The best chance of a goalless first half fell to Wycombe’s Adebayo Akinfenwa, who controlled with his chest and outmuscled three defenders only to shoot straight at the keeper.
With the tension beginning to mount, Wycombe were awarded a free-kick on the edge of the area after Akinfenwa was brought down.
Up stepped McCarthy, who left keeper Chris Dunn motionless in the Walsall goal as Adams Park erupted.
Walsall threw on all three substitutes but even six minutes of stoppage time was not enough for them to come back as Wycombe held on for the victory.