Sam Allardyce was left to count the cost of a series of defensive lapses as West Ham United went down 4-2 at home to Reading on Saturday afternoon.
The Hammers started strongly and took the lead through Carlton Cole in the eighth minute, before going on to enjoy much the better of the opening half. A crazy period of ten minutes from the hosts just before half-time turned the game on its head as Reading snatched two quickfire goals from Kaspars Gorkss and Noel Hunt.
A penalty converted by veteran Ian Harte made it a 3-1 advantage before Ricardo Vaz Te pulled one back to give West Ham hope. The joy was short-lived, however, as a lucky ricochet put Mikele Leigertwood in to restore the Royals' two-goal advantage and dampen any hopes of a Hammers fightback.
"I'm really disappointed that we have gone and let ourselves down with ten minutes of madness defensively at the end of the first half," Big Sam said. "We looked so comfortable and good and then we turned it into a massive uphill struggle for ourselves.
"Not just by going 2-1 down in the space of two minutes but also through conceding a really poor penalty so the 10 minutes of madness have cost us. That made life so difficult for us but even then we clawed ourselves back into the game at 3-2.
"I thought we would go on and get a result at that point but we went and shot ourselves in the foot again by gifting them a fourth."
The start made by Big Sam's side showed how much they wanted to overturn the one point advantage Reading held going into the game and they quickly went about knocking their visitors into a shell-shocked state.
"We wanted to start the game well. You can't give encouragement to teams like Reading and we were really pleased with how we made them struggle. We looked like every time we created an attack that we could get some success and several times we opened them up."
Recent results have left Big Sam frustrated at his team's end product, but after goals from two of his forwards, it was issues at the other end of the pitch that he said had cost his side a result.
"I never thought before, based on where we were and how we have done, that we would ever concede four goals here. But we have and that's why we have lost; our defensive unit today didn't function as normal and that was a big blow to us which ultimately cost us after such a good start to the game.
"How we didn't equalise at the very end of the first half is beyond me. The corner came in and the header got scrambled off the line. If we go in at half time at 2-2 then it would have given us a massive lift.
But it didn't and then we made the substitutions, waited for our chances and got to 3-2 with Vaz Te's great header."
The loss was West Ham's first in 12 games and their first at home since 3 December and although the win moves Reading further into the driving seat for automatic promotion, the race is not completely over yet according to Big Sam.
"It's not over yet but we have made life extremely difficult for ourselves as we have allowed Reading to open up a four point gap on ourselves.
"There is no room for error in the remaining six games, dropped points aren't an option if we want to get out of this league."
If West Ham are to get their promotion charge back on track, they will need win both Easter weekend games, starting with Barnsley away on Friday night. Birmingham follow three days later, with no less than six points needed from the two games to keep West Ham in the automatic promotion picture according to Big Sam.
Allardyce added: "We need to clear their minds and get over this as quickly as possible and put it behind us. There is nothing we can do about it now, we should focus on how well we played in the first 43 minutes and how if we hadn't gifted them two goals then we would've carried on in that way."