Swansea City Under-21s suffered late heartbreak as Mark O’Mahony’s stoppage-time header gave Brighton & Hove Albion victory, and denied the visitors the point they needed to guarantee a place in the knockout stages of the Premier League Cup. 

The Swans only needed a draw to seal a spot in the next round, with a game at Aston Villa - who currently sit top of Group A - still to come.

Defeat sees Swansea remain second in the table - the top two go through - but the Seagulls have closed to within two points of Anthony Wright’s side ahead of the final round of fixtures.

Both sides had their chances with Cameron Congreve, Filip Lissah and Ben Lloyd all going close for the Swans. 

But the hosts kept their chances progressing alive with a 93rd-minute header from O'Mahony.

Glory Nzingo had made his first start for the Swans since returning from injury, whilst Nathan Broome made his second appearance for the young Swans in goal.

With the hosts knowing nothing less than a win would do, it was a quick start for Albion and Casper Nilsson found the net inside five minutes, only for the offside flag to cut short the celebrations.

Down the other end, Joel Cotterill fashioned an effort that flew over the bar, after the midfielder had initially found Nzingo’s run into the area.

Congreve then met a Nzingo cross after a short free-kick taken by Lim Smith, but the 19-year-old’s final touch was blasted over the crossbar.  

The visitors were enjoying a good spell of possession, but a quick counter-attack from the Seagulls saw Freddie Kavanagh’s shot ruffle the side-netting.

It then took a crucial tackle from Richard Faakye to keep out Samy Chouchane as the opening half ended goalless.

The second period started at a frenetic pace.

Lissah forced a diving save out of Hugo Fisher after the centre-back was picked out by Smith from a set-piece.

Brighton swept straight down the other end, where Broome kept out a right-footed effort from Harry Howell as he raced through on goal.

Congreve then scuffed a deflected effort wide after fending off his marker twice outside of the penalty area.

In the final quarter, the Swans looked the more likely to break the deadlock.

Lloyd linked up well with Mitchell Bates down the left, where the latter delivered a fine ball in for Smith to head goalward.

The Scot’s effort looked like it had hit a hand, but the referee waved any penalty appeals away.

Lloyd got involved again and he made a slick turn before hitting a shot straight at Fisher, after Congreve had teed him up from the left flank.

But, in stoppage time, the hosts found the breakthrough and kept their chances of sealing a place in the last-16 alive with a 93rd-minute header from O'Mahony settling the contest.

Brighton Under-21s: Hugo Fisher, Benjamin Jackson, Imari Samuels, Freddie Simmonds, Leigh Kavanagh, Jack Hinchy (captain), Casper Nilsson, Samy Chouchane, Josh Duffus, Luca Barrington, Harry Howell.

Substitutes: Joe Knight, Tommy Reid, Mark O'Mahony, Bailey Smith, Odel Offiah.

Swansea City Under-21s: Nathan Broome, Harry Jones, Lincoln McFayden, Mitchell Bates, Filip Lissah (captain), Richard Faakye, Liam Smith, Joel Cotterill, Maliq Cadogan, Glory Nzingo, Cameron Congreve.

Substitutes: Charlie Veevers, Ewan Griffiths, Ben Lloyd, Kian Jenkins, Teo Minchev.