Gary Roberts and Armand Gnanduillet's second half goals helped Chesterfield came from behind to beat Northampton 3-1 at Sixfields.
High-flying Chesterfield forced the issue in the opening period which produced three corners in quick succession for the visitors but Northampton saw out the danger.
And it was the struggling Cobblers who broke the deadlock in the 15th minute. Goalkeper Thomas Lee brought down Hallam Hope in the box and Darren Carter tucked away the ensuing spot-kick into the bottom corner of the net.
Matty Blair went close for Cobblers but the first half failed to produce many clear-cut openings in difficult conditions. Chesterfield equalised in the 25th minute when Dan Gardner beat Matt Duke from a tight angle after good work from Sam Morsy.
After the restart James Hurst was denied by Lee but it was the visitors who went ahead in the 53rd minute when Roberts beat Duke from 15 yards to notch his seventh league goal of the season after being set-up by Gardner.
Roberts went close to grabbing his second goal moments later when his close-range header was blocked and Gardner also saw his shot from the edge of the box blocked.
Blair came closest to putting Cobblers back on level terms in the closing stages but the basement side found it difficult to make openings as they slumped to another defeat which was confirmed in the 87th minute when Gnanduillet beat Duke from 15 yards.