Nick Haycock felt that small margins determined the outcome of the Development Squad's 2-0 Barclays Under-21 Premier League defeat to Liverpool at Rush Green on Friday night.
The Hammers were the dominant force for the most part of the first half and were unlucky not to be ahead when Elliot Lee's acrobatic effort rebounded off the post before rolling clear of danger.
As the first period drew to a close, Liverpool went ahead when Kristoff Peterson's shot struck Jack Dunn and the goalkeeper Raphael Spiegel failed to deal with his effort which snuck past him into the corner.
Dunn wrapped the game up for the away side with 13 minutes left when he put the finishing touches to a flowing Liverpool move, leaving Haycock ruing the fine margins which cost his side.
He told West Ham TV: "I enjoyed the game, I've just said to the boys in there that it was a nearly night.
"The game itself, we were unlucky not to go 1-0 up with Elliot's chance and Sebby follows up but it just shaves the post. When Elliot hit the post they're the ones that can hit the post and go in or hit the post and come out for someone else to tap in, on this occasion it went clear of danger.
"The goal before half-time was a mistake, it's a deflection, but it's a mistake. We had to live with that and try to raise ourselves at half-time because we felt that the minimum we deserved at half-time was to be level.
"On chances I thought we deserved to be in front, in terms of possession you expect a Liverpool team to have a lot, but again I thought we had some good passing moments ourselves at times. We're working on building a new team, with young players in there, and they'll only learn from playing in games like that."
Liverpool who sat second in the table at the start of the night, fielded a strong line-up including regular first team duo Lucas Leiva and Mamadou Sakho amongst their starting XI.
Despite the visitors' strong line-up, the home side had them on the back foot for the majority of the first half and Haycock admitted his disappointment at conceding just before the interval.
"I think they started the game better, we obviously had the first chance and I thought we got to grips with how we were going to get after the ball which I was pleased with because we've done a lot of work on that.
"I thought we grew into the game and you're thinking that you're going to go in 0-0 and then the deflection doesn't kill you, but deflates you a little bit and you have to raise them again. I've seen games where Liverpool will go and get two, three, four because of that and I never felt that would happen because of the sheer endeavour that the boys show most weeks.
"At times, if the final pass, cross or set-piece would have been a little bit better then I thought there were goals there for us tonight. It was a nearly night against a good Liverpool team."
Despite the loss, the Development Squad boss felt his players could only learn from the match, particularly young midfielder Josh Cullen.
"You've got Josh Cullen who's only 17 years old still, playing against a Brazilian international. People will say it's about winning, yes, but I've gone in there and said 'don't be happy that you've lost the game, but put the experience in your pocket'.
"It was a great experience for him in particular because it's in the middle of the park and the heat of the battle where he wants to be and it was a great night for him."