Brentford exited the FA Youth Cup at the Third Round stage as they let slip a 2-0 lead inside the final 15 minutes to lose to a Hull City side propelled to victory by a William Annan hat-trick.
The Bees dominated the majority of the first 75 minutes.
They had a two-goal lead thanks to a James Ferry penalty and a superb Courtney Senior goal.
But soon after The Bees got the two-goal advantage the game changed.
Annan scored two to take the game to extra time and then curled home a free kick to win it for the home side.
Brentford will go away wondering how they lost the match.
The young Bees looked comfortable in their surroundings.
They passed the ball well, looking to get their four attacking players running at the home defence.
Both Seika Jatta and Senior on the wings looked to have the beating of their full backs and Bradley Clayton found pockets of space to play in.
Hull were slightly more direct than their visitors but had a real threat in right winger Devonte Morton, who combined well with tricky striker Jarrod Bowen.
Morton had the first sight of goal for the hosts, lifting a shot over from 25 yards, but Brentford dominated the opening exchanges.
Clayton forced Jonathan Hirst in to an early save with an early shot and then blasted over when well-placed after Senior had, not for the last time on the night, beaten Jacob Rose.
Clayton shot wide again soon after following a good run forward by Tom Field and the two then combined, with Senior, to put Kingsley Eshun away one-on-one with Hirst but he poked his effort wide.
Hull’s attacks were few and far between in the first half hour, as Brentford controlled posession, but when they did get in to attacking areas they looked capable of scoring.
Josh Clackstone fired a free kick over the bar and moments later the home side had a great chance to go in front.
Brentford lost the ball in midfield and Morton fed Annan, when the ball came back in Morton was crowded out but Bowen got away a shot that forced Nik Tzanev to spring high to his left to superbly tip away.
Bowen went close again soon after when he tricked his way inside and let fly with a left foot shot that took a deflection and looked destined for the net before Tzanev brilliantly went full stretch to his right and turned it on to the post and wide.
Tzanev saved an acrobatic effort from Matthew Hinchcliffe soon after but Brentford looked the better side and set about making the score line show it.
Senior poked a one-on-one wide after being put through by the influential Clayton and he then had a shot blocked.
Field shot wide after Clayton again linked the play in midfield before, late in the first half, The Bees went ahead.
After a spell of possession Jatta tried to burst in to the box but only gave the ball to Morton, Senior swooped in as the Hull man failed to control and was then brought down by the winger.
Ferry stepped up to calmly send Hirst the wrong way from the spot and give Brentford a half time lead.
Hull were noticeably better after half time, keeping the ball better and moving it up the pitch in an aesthetically pleasing manner.
Brentford were forced to work harder in midfield to keep them at bay – a Morton shot was blocked and Bowen blasted over after exchanging passes with Jake Buckle.
The Bees weathered Hull’s early storm, however, and began to take control of the game again.
They were able to keep possession in a way their hosts couldn’t at that stage and although there weren’t many chances, The Bees had the initiative.
A Reece Cole free kick flew across the face of goal, just eluding Clayton and Field, and Seth Owens went ambitiously for goal from 30 yards after a run from deep.
Hirst just about managed to keep out a Cole shot but he was left helpless moments later when The Bees doubled their lead.
Cole, who had quietly dominated the centre of midfield after coming on, released Senior in the inside left channel, he once again raced past Rose before lashing the ball in to the top corner.
Tzanev had saved a curling shot from Morton but Brentford had complete control and Senior’s goal looked as if it would settled matters.
But The Tigers roared back.
They reduced the deficit within three minutes when Josh Tymon delivered a cross from the left and Annan arrived late at the far post to head in.
And with five minutes remaining, they were level.
Brentford were a man down with Audrius Laucys off receiving treatment and tried to play out from the back, Annan won the ball, drove in to the box and let fly with a shot that Tzanev could only push on to the post before watching it roll in.
The home side had the upper hand and came closest to winning it in the first 90 minutes.
Ben Hinchcliffe shot narrowly wide of the far post and then blasted over from the inside left channel.
Annan then forced Tzanev in to a diving save before, with the last action of the 90 minutes, meeting a Daniel Batty corner with a looping header that Owens nodded off the line.
Cole had shot wide late on for The Bees and it took an important tackle from Ellis Barkworth to prevent Eshun finishing off after Senior had got away.
But Hull had the momentum at the end of the 90 minutes and maintained it in to extra time.
Rose blasted well over for the home side before, when a corner was half cleared, a Bowen shot was blocked on the line by Owens and Batty lashed the loose ball inches wide.
Tzanev saved a Clackstone free kick, and the follow-up from Bowen, but he was left helpless moments later when Annan completed his hat-trick, curling a free kick in to the far corner from the left side of the penalty area.
Brentford were under the cosh, and only had a blocked Field shot to show for their first half efforts, but fought to maintain their place in the cup in the second half of extra time.
Gradi Milenge had the ball in the net, only for the goal to be ruled out for offside, and Jeremiah Kamanzi was unable to turn in a Chris Mepham cross, although if he had left it Clayton was arriving to convert.
Brentford pressed more and more and left gaps at the back.
Tzanev saved from Bowen and then saved at the feet of the Hull striker as he tried to get on to an Annan pass,
Senior had a shot blocked for The Bees and, when a free kick was half cleared, Cole was unable to get enough on an acrobatic effort to turn it home.
Time was running out for The Bees and Tzanev saved from Luke Lofts to keep them in it as the game entered the dying stages.
Brentford continued to throw men forward but couldn’t find a goal and Hull took their place in the FA Youth Cup Fourth Round.
Hull City Youth: Jonathan Hirst; Jacob Rose, Josh Clackstone, Matthew Hinchcliffe (sub Joe Pugh 114 mins), Josh Tymon; Devonte Morton, Daniel Batty, Ellis Barkworth, Jake Buckle (sub Ben Hinchcliffe 68 mins); Jarrod Bowen (sub Luke Lofts 120 mins), William Annan
Subs (not used): Mitchell Langton, Tyler Hamilton
Bookings: M. Hinchcliffe (80 mins), Barkworth (116 mins)
Brentford Youth: Nik Tzanev; Audrius Laucys (sub Chris Mepham 90 mins), Gradi Milenge, Seth, Owens, Tom Field (sub Jeremiah Kamanzi 105 mins); James Ferry (sub Reece Cole 53 mins), Zain Westbrooke; Seika Jatta, Bradley Clayton, Courtney Senior; Kingsley Eshun
Subs (not used): Cameron Greaves, Makhosini Khanye
Bookings: Ferry (34 mins)
By Chris Wickham