Lincoln goalkeeper Trevor Carson was the hero and villain as leaders Chesterfield won for the first time in six matches in a 2-0 victory.
In-form Lincoln created the first chance of the game after just five minutes when Chesterfield keeper Tommy Lee produced a good save to deny Stephen Hunt.
But they were gifted a 15th-minute opener when Carson mis-controlled a back-pass from Julian Kelly, allowing Craig Davies to pass the ball into the empty net.
Carson made up for his error six minutes later when he guessed right to save a Davies penalty after the Chesterfield striker was pulled to the ground by Adam Watts.
Chesterfield were denied a second when Danny Whitaker's header was cleared off the line by Watts, but Lincoln continued to look dangerous and went close when Ashley Grimes hooked inches wide.
Only the linesman's flag denied Gavin McCallum a Lincoln equaliser when he was ruled offside, but Chesterfield secured all three points when Dean Holden bundled the ball home from close range on 83 minutes after poor marking in the Lincoln defence.