Town's U21 side rounded off their Professional Development League Two South campaign with a disappointing 2-1 home defeat against Fleetwood Town on Tuesday morning, with captain Tommy Taylor netting in the second half.
The young Blues fell behind in just the second minute when a long ball over the top wasn't dealt with and David Animasaun burst through and finished well, despite a last-ditch attempt to block from Jacob Mazionis.
John McGreal's side should have been back on level terms four minutes later when a low ball in from the right was turned goalwards by skipper Taylor but his shot was blocked on the line and then Rio Morgan fired the rebound off target.
Minutes later, Animasaun teed up Elidon O'Boyle after a clearance from the back was intercepted but the midfielder shot wide from close range.
On 24, the visitors did double their lead though when O'Boyle's long-range drive was parried by Woody Williamson and Animasaun reacted first to turn the rebound home.
At the other end, Steven Turner's low shot from the edge of the box was comfortably gathered by visiting keeper Oliver Bellelia, before Williamson got down well to block Pele Smith's effort after a cross from the right.
The closest Town came to pulling a goal back before the break was when Mazionis headed Turner's corner just over the bar late on in the half.
Youngster Charlie Wood, who recently signed from Needham Market, made his U21s debut as he was introduced at the break. The midfielder replaced 17-year-old trialist defender Hamid Seisay, who has most recently been with Rotherham United.
Williamson was called into action again to deny Rylee Wilkinson at his near post, before Wood headed a left-sided corner over as Town tried to find a way back into the game.
On 74 they did halve the deficit when Morgan's long-range effort was parried by Bellelia. Turner returned the ball back into the box from the right and after a scramble and the visitors appealing desperately for offside, Taylor fired the loose ball home from six yards out.
Four minutes later Taylor hit a low free-kick from 25 yards out that Bellelia gathered at the second attempt, while Morgan saw a snap shot deflected wide and Corbin Mthunzi, who recently joined the Blues from Brighton following a trial, looped a header over the bar.
The Fleetwood defence held firm though and Town were left to rue their slow start, which ultimately ended up costing them.
The result leaves the Blues in fifth in the 11-team PDL2 South table, although they will finish in sixth if Cardiff get a draw or all three points against Burnley in their final game later this afternoon.
U21s: Williamson, Babb (Elliott 72), Boniface, Mthunzi, Mazionis, Turner, Boswell (Adebayo 61), Seisay (Wood 46), Pitts (Mauge 61), Taylor, Morgan. Unused: Binns.