Fabio Tavares’ brace proved the difference as Swansea City Under-23s were beaten by Coventry City at Landore in the Professional Development League.
The Swans had looked set to pick up a point from this encounter, which was watched by first-team head coach Russell Martin, after sub Tarrelle Whittaker levelled with nine minutes left.
But Taveres, who had opened the scoring in the 16th minute, regained the lead just four minutes after the Swans had equalised, while Richard Dinangia added further gloss on the visitors’ victory with the last kick of the game.
Victory helped Coventry maintain top spot in the North section, while the Swans remain eighth in the South division.
The Swans returned to a more youthful team compared to the starting XI that had beaten Watford earlier in the week thanks to the inclusion of several first-team players in need of game-time.
The first half conjured a string of opportunities, with both teams creating chances.
The Swans were first to attack after three minutes, with Azeem Abdulai winning possession before teeing up Ben Lloyd, but his 20-yard effort was padded wide for a corner by keeper Cian Tyler at full stretch.
Home keeper Jamie Searle was then called into action as Coventry launched a counter attack and when a cross was diverted goalwards by Jacob Jones, only for the New Zealander to react well and swat the ball away from danger.
The Sky Blues then saw Tavares fire over after Lloyd had lost possession, but the striker would make up for that soon after.
After the Swans played a quickly-taken goal-kick, Tavares pounced to claim possession and fire home from inside the box.
O’Leary’s side went in search of an instant equaliser, with Rio Campbell intercepting captain Jonny Ngandu’s pass before finding Jaden Forrester. He cut inside onto his right foot before letting rip, and despite appeals for handball, referee Claudio Gavilucci wasn’t convinced.
This end-to-end encounter continued with Campbell’s intercepted pass allowing Tavares to set up Dinangia, but his effort was deflected over.
The Swans could, and should, have levelled just before the half-hour mark as Lloyd’s pinpoint cross found Forrester in the box, but his header from around 10 yards out dropped onto the top netting.
After the break, Searle was alert to make a fine save low down to deny Aaron Evans-Harriott, before the Swans thought they had finally equalised.
Lincoln McFayden looked to have kept a ball in play despite Coventry shielding the ball out for a goal-kick, and the wing-back tapped inside for Forrester to blast home. Up went the flag, signalling for a goal-kick, and the Swans’ effort was chalked off.
The hosts kept plugging away, and Dylan Morgan went close on two occasions from range, but he was kept out by Tyler.
This entertaining encounter continued with only the post saving the Swans when Dinangia beat Scott Butler for pace before cutting inside and seeing his low shot strike the woodwork.
Coventry did go one better soon after, only this time the flag came to the Swans’ rescue as Tavares slotted home only to be called offside.
The Swans, though, got the goal their efforts had deserved. After Coventry looked to the assistant to lift his flag for offside, the Swans pounced and sub Whittaker fired home from close range.
That looked to have done enough to give the Swans at least a point, but Tavares had different thoughts.
Dinangia drove into the box and drew Searle off his line, and his perfect pass allowed Tavares to sidefoot home into an empty net.
And Coventry would add another with the last kick of the game as provided turned scorer with Dinangia racing in on goal before beating Searle from inside the box.
Next up for the Swans is another home clash with Cardiff City in Landore on Monday night (7pm).
Swansea City Under-23s: Jamie Searle, Harry Jones, Jacob Jones, Azeem Abdulai, Scott Butler, Ben Erickson (captain), Lincoln McFayden, Ben Lloyd (Joel Cotterill, 62), Jaden Forrester (Tarrelle Whittaker, 62), Dylan Morgan, Rio Campbell (Sam Leverett, ht).
Subs: Nico Hansen, Adrian Akande.
Coventry City Under-23s: Cian Tyler, Blaine Rowe, Leslie Duru, George Burroughs, Aaron Evans-Harriott (Evan Aisowieren, 90), Ryan Howley, Fabio Tavares, Jonny Ngandu (capt), Ricardo Dinangia, Harrison Nee (Isaac Moore, 90), Josh Pask (Julien Dacosta, ht).
Subs: Fionn O’Brien, Charlie Callaghan.