The Robins put on a strong showing against promotion chasing Derby County but fell the wrong side of a 2-1 scoreline.
Liam Sercombe put the Robins ahead at Pride Park but goals from Max Bird and James Collins earned the three points for the hosts.
After the defeat, manager Darrell Clarke said:
"The overriding emotion again is frustration. It's a blatant penalty for me but I was also frustrated with how we defended the set-piece.
"We've got a good honest group but can they raise those quality levels, can they manage situations better. Individually and collectively we have to be better at that."
It was the Robins who came out the blocks the fastest and brought Rams keeper Josh Vickers straight into action after just three minutes.
Some determined running down the left flank from George Lloyd saw him find Sercombe in the area, but his effort was beaten away by the Derby shot stopper.
Clarke's side continued to press and probe the Derby defence and had another chance on 20 minutes when Rob Street and Sean Long's hard work won the ball in the area.
Sercombe this time had his own sight at goal, but his delicately chipped effort was held by Vickers.
The hosts began to get hold of posession and had their first sight at goal not long after when Nathaniel Mendez-Laing's corner was headed over at the near post by striker James Collins.
The rest of the opening 45 saw little else action, with Eiran Cashin's looping header landing on the roof of the net five minutes before the break.
Into the second half and just five minutes after the restart the Robins went ahead, with Sercombe finding the net and his seventh of the season.
Captain Long made his way into the area before picking out the midfielder, whose deflected effort rolled past Vickers into the bottom left corner.
Just moments later and the Robins had a massive appeal for a penalty waved away by referee Leigh Doughty.
Defender Louie Sibley looked to have brought down Lloyd in the area but the referee's decision was made, and it proved costly minutes later.
It was Max Bird who was on hand to whip the ball into the back of the net from a crafty set-piece to level the scores on the hour mark.
Sercombe came almightily close to a second just moments after when an incredible acrobatic effort had to be saved on the stretch by Vickers.
And as the clash looks destined to finish one a piece, the hosts snatched the three points 10 minutes from time as Collins volleyed home from inside the area to send the Robins home empty handed once again.
DERBY COUNTY (4-4-1-1): Vickers; Wilson, Nelson, Cashin, Sibley; Mendez-Laing, Hourihane (C) (Bradley 64), Bird, Blackett-Taylor (Thompson 64); Barkhuizen (Fornah 64); Collins. Subs not used: Wildsmith (Gk), Ward, Fapetu, Robinson
CHELTENHAM TOWN (3-5-2): Southwood; A.Smith, Davies, Freestone; Long (C), Sercombe (Kinsella 65), Pett (Thompson 77), Bonds (Harrop 65), Ferry (Butler-Oyedeji 85); Lloyd, Street (Keena 46). Subs not used: Pardington (Gk), L.Smith
REFEREE: L Doughty
ATTENDANCE: 27,040 (712 from Cheltenham)