Yeo, back with the Imps for a second spell, thought he had marked his return with an 82nd minute goal and his fourth successive winner against the Stags, but after Dean Keats' free-kick pile driver had only been parried by veteran keeper Kevin Pressman, Yeo could only head the close range rebound against the post.
Yeo was almost left ruing his miss in the final minute when Mansfield substitute Richie Barker's dramatic diving header from a Gus Uhlenbeek cross flew narrowly wide.
Yeo's inclusion was the only change made by caretaker John Schofield surprisingly in charge after manager Keith Alexander and his assistant Gary Simpson were told to stay away from the club less than 24 hours earlier.
Despite the upheaval the Imps made the better start with Yeo's low 30-yard drive well held by Pressman.
The best early chance fell to Mansfield. Stephen Dawson's cross found Adam Rundall unmarked in the area and, when his shot was cleared off the line by Gareth McAuley, Mansfield's loan striker Alan Russell blazed the rebound over an empty net.
Teenage striker Nathan Arnold, who had scored on his debut five days earlier, was then denied by Alan Marriott's good stop.
An even better save, this time by the flying Pressman at the other end, prevented Keats from giving Lincoln the lead with a curling 20-yard free kick.
Mansfield started the second half on top. Dawson slipped when he looked certain to score after a penetrating run by full back Jake Buxton and then Alex Baptiste was blocked by Paul Mayo's last ditch tackle.
As Lincoln fought back Yeo created a fine chance for Keats, but as he shaped to score Rhys Day somehow slid in to block his shot.