Blackpool secured a play-off spot with a fifth straight win courtesy of a late winner from Keith Southern.
On-loan Barnsley defender Robbie Williams scored the opener with a brilliant free kick from 18 yards out.
But Williams then conceded a penalty, after he fouled Steve Gillespie, that Robins' captain John Finnigan scored.
Scott Brown pulled off a great save from Wesley Hoolahan's effort but could do nothing about Southern's winner that was struck home from 25 yards out.
Cheltenham: Scott Brown, Gill, Townsend, Duff, Armstrong, Melligan, Finnigan, Bird, Spencer (Connor 87), Odejayi, Gillespie.
Subs Not Used: Caines, Lowe, Connolly, Reid.
Booked: Melligan, Finnigan.
Goals: Finnigan 51 pen.
Blackpool: Hart, Barker, Jackson, Evatt, Williams, Brandon (Gillett 79), Southern, Jorgensen, Hoolahan (Gorkss 89), Morrell, Parker (Forbes 83).
Subs Not Used: Coid, Fox.
Goals: Williams 39, Southern 85.
Ref: P Miller (Bedfordshire).