Paul Tisdale rued poor defending from his Exeter side as they fell to a 2-1 derby defeat at West country rivals Bristol Rovers.
John-Joe O'Toole acrobatically volleyed home a Chris Beardsley cross to snatch all three points, having netted a last-gasp FA Cup winner at Crawley in midweek.
The former Colchester player had earlier confidently converted a 21st-minute penalty, just seconds after the visitors had gone in front courtesy of Lee Brown's own goal.
Tisdale admitted: "We have given away two bad goals, one of them straight from the kick-off after we scored, and the result is all that counts.
"I threw on two attacking substitutes and ended the game with three strikers because I felt we were on top in the second half and could go on to win.
"But we have to defend better. Some of our younger players did extremely well again, which is a positive, but some of the experienced ones are letting them down.
"We have lost too many games that we should have won or at least drawn over the past month or so, which is disappointing."