Luton Town were defeated 2-1 by Cardiff after the Welsh side struck a late winner.
It looked as though Luton had done enough to take a point after Matt Pearson equalised after Aden Flint’s opener.
But in the sixth minute of added time, former Luton striker Isaac Vassell scored on his Cardiff debut to win the contest.
It was late heartache for the Hatters, who enjoyed most of the possession and a few decent chances against a side relegated from last season’s Premier League.
In a scoreless first half, quick bursts in attack yielded chances for the Bluebirds, as Josh Murphy had a few early chances come close, defender Sean Morrison was denied by goalkeeper Simon Sluga, and Gavin Whyte just failed to reach Murphy’s low cross-shot.
Luton did have some first period opportunities, with Callum McManaman seeing one shot saved by Alex Smithies and a further header go off target.
Cardiff’s opener came a few minutes after half-time, when Flint turned in a Murphy’s free-kick.
The best chance for an equaliser in the opening stages after the Cardiff opener fell to James Collins, who saw a first-time shot ripple the side-netting.
Luton’s equaliser came from a set-piece of their own, as Pearson got a head on Luke Berry’s corner. It makes Pearson the third Luton defender to score so far this season, after Sonny Bradley and Martin Cranie scored in the season opener.
But just when it seemed like Luton were about to hold out, Cardiff won in added time. It was a debut goal for ex-Hatter Vassell after his deadline day move from Birmingham City, as he turned in Junior Hoilett’s cross within five minutes of coming on as a sub.
Graeme Jones’ side now turn their attentions to the EFL Cup, as they host Ipswich Town at Kenilworth Road in their First Round tie on Tuesday.