Blues were unable to get back to winning ways in League 2 as they suffered a 3-0 defeat at the hands of Exeter City at St James' Park.
Two goals from John O'Flynn, either side of a header from Scot Bennett, sealed a comfortable win for the home side - but it could all have been so different had the linesman judged Barry Corr's header to have gone over the line.
Unfortunately for Blues, he didn't, and having gone 1-0 down before half time, they were unable to find a route back into the game before two late goals sealed the win for the home side.
Paul Sturrock made one change from Tuesday's penalty win against Oxford in the Johnstone's Paint Trophy as Marc Laird came in to replace Anthony Straker.
The first opening fell the way of the home side. A poor kick from Paul Smith was played back over the top for O'Flynn to run onto, but his tame shot was held by Smith.
At the other end, Blues were putting some good passing moves together but unable to get a clear sighting of goal. Their best chance fell the way of Gavin Tomlin, but his shot was deflected behind for a corner.
The home side did have the ball in the back of the net midway through the first half, but the flag had been raised by the assistant referee on the far side for offside.
Blues were trying to get their passing game going, but were forced into a change just before the half-hour as Laird was replaced by David Martin due to injury.
Minutes later and Blues were within inches of going ahead Tomlin and Kevan Hurst linked up well down the right, and the former's cross was met by Barry Corr. The striker's downwards header bounced off the bar and was cleared by Bennett on the line.
Blues appealed, but the assistant referee was unmoved and play continued.
Michael Timlin had moved central following the injury to Laird, and it was he who had Blues' next chance. Hurst's corner wasn't cleared properly and Timlin, waiting on the edge of the box, fired just wide on the half-volley.
But having been on top, Blues fell behind in the 42nd minute. O'Flynn was played in down the right hand side of the penalty area and fired the ball low across Smith and in off the far post.
The home side began the second half on the front foot as Alan Gow went close, but fired just wide after beating two men.
Blues first chance of the half came with their best move of the game up to that point. Timlin switched the ball for Sean Clohessy to lay it off for Tomlin, but the striker's effort was cleared behind for a corner.
Exeter had certainly improved since the break, and almost doubled their lead with twenty minutes to go. Danny Coles' header though, when unmarked in the area, was straight at Smith.
Sturrock made his second change with twenty minutes to go as Elliot Benyon replaced Alex Woodyard. And the striker almost made a telling contribution immediately as he teed up Tomlin, but he fired over with his left foot.
But as Blues looked for a route back into the game, it was Exeter who found the back of the net to double their lead. Matt Oakley's deep corner found the head of Bennett who looped it back over Smith.
The Johnstone's Paint exploits seemed to have given Exeter the edge as the game wore on and it was 3-0 moments later. Excellent work from Jimmy Keohane put him through, but he unselfishly teed up O'Flynn for a tap-in.
Neil Harris came on to make his first appearance since September, but Blues were unable to grab a consolation goal. They must pick themselves up quickly now ahead of the trip to Brentford in the FA Cup.
Blues: Smith; Clohessy, Cresswell, Phillips, Barker; Laird (Martin 28), Timlin, Hurst, Woodyard (Benyon 70); Corr (Harris 89), Tomlin, Subs not used: Leonard, Bentley, Prosser, Straker.