Nick Haycock was left pondering what might have been after his Development Squad surrendered a two-goal lead, before ending up on the wrong end of a 3-2 Barclays Under-21 Premier League defeat at home to Tottenham Hotspur.
The evening had begun so well, with skipper Dan Potts and then Sebastian Lletget handing the Hammers a commanding 2-0 advantage at the interval.
But once Spurs had seized the second-half initiative, West Ham were unable to wrestle back control, succumbing to a deflected Simon Dawkins goal, Lewis Holtby's stunner and a controversial late Shaquile Coulthirst winner.
In all, it amounted to a frustrating outcome for the U21s boss, who bemoaned a host of missed chances in the first half and a lack of leadership in the second.
WATCH NICK HAYCOCK'S FULL INTERVIEW ON WEST HAM TV
He told West Ham TV: "It was a game of two halves. We were unlucky not to come in four, five goals to the good. That's being realistic.
"[We've had one] cleared off the line. Paul McCallum has had a great header, he should score, he knows that. He's had a dink over the 'keeper which was easy for a technical player, which he is and he score those goals. And then Elliot has just dragged his shot wide of the post with his left foot, after some great movement.
Dan Potts celebrates his opener with Sebastian Lletget and Blair Turgott
"At half time, [I told them] keep doing the same, don't drop too deep, make sure you retain possession when we can and we didn't do that!
"We defended too deep, we gave too many aimless long balls and then when it went up it didn't stick. They looked a little bit more resilient in the second half, and a bit more aggressive in their defending, which helped them get back in the game."
While there can be no argument that Spurs enjoyed the upper-hand after the interval, Haycock was justly aggrieved with the manner of the visitor's three goals, not least the 86th minute winner.
He continued: "A deflected goal for the first one, a great strike from a German international, and then, disappointingly, making no excuses, but the winner's offside. We've just seen it. It's a great bit of skill from the kid to dink it over us, but it's offside and I thought over the course of the game a draw would probably have been a fair result.
"We've had the elation of winning in the last five minutes, we've now got to deal with the disappointment of losing in them too."
Frustrating though it might be, Haycock knows that Friday's difficult second half, was due, in part at least, to a lack of experience. The returning George McCartney departed the action after the hour, with the Hammers losing their way somewhat thereafter.
"George McCartney's playing and the instructions were 60 minutes, so we brought him off after the hour. I think that change affected us slightly, but they've got to learn to deal with that sort of thing. If you're not right for 95 minutes you're going to get punished.
"I don't think we had the leadership in there to have the confidence to play. That's the disappointing thing, because at 2-0 you should control the game and we allowed them to control us a little bit.
"Had Kevin Nolan, Mark Noble, or James Collins been playing tonight, at 2-0 up, they don't let a team back in it. They're the fine details, we'll make sure that's the message and we'll be ready for Newcastle."