Wycombe had earlier created and wasted a host of chances. The main culprit was Craig Faulconbridge who had four chances with his head, but failed to get his efforts on target.
The Imps were denied what seemed a clear penalty when Blues defender Tony Craig felled Martin Carruthers.
Lincoln should have taken the lead right on half-time, but Carruthers' shot was half saved by Frank Talia, and as the ball dropped dangerously Danny Senda miraculously cleared off the line.
The second half lacked the excitement of the first. Once again Faulconbridge continued to waste chances, managing to hit the post when it seemed easier to score from six yards after a minute of the restart. Sixty seconds later Faulconbridge yet again blasted over from six yards.
As the game wore on, Lincoln began to impose themselves. Jamie McCombe shot wide from six yards, wasting his side's best chance.
The breakthrough came after 89 minutes. Assistant manager Keith Ryan sparked off joyous scenes all around the Causeway Stadium when he met a Guppy corner with a thunderous header into the net to steal all three points.