Chesterfield new boys Gary Roberts and Eoin Doyle marked their home debuts with the goals that sent Cheltenham crashing to a 2-0 defeat at the Proact Stadium.
Roberts gave the Spireites a first-half lead and although the Robins improved after the break, Doyle settled it a minute from the end.
The hosts started impressively with Marc Richards heading wide after three minutes and they deservedly went ahead 20 minutes later when Richards played Roberts in and he held off two challenges beforebeating goalkeeper Scott Brown from 12 yards.
Roberts was a constant threat and it needed a good diving save by Brown to keep out his 25-yard free-kick on the stroke of half-time, but Cheltenham almost equalised prior to the break when Byron Harrison's shot was cleared off the line by Ryan Edwards.
Cheltenham substitute Ashley Vincent saw his 54th-minute header cancelled out by an offside flag and Harrison was denied by stopper Tommy Lee five minutes later
Brown kept the visiting side alive with saves from Tendayi Darikwa and Jay O'Shea but Doyle secured the points at the death with a low finish from 15 yards.