Manuel Pellegrini admitted that his side are conceding too many goals and rued poor decision-making from the officials after West Ham slipped to a 2-2 draw with Leicester on Saturday.
The Hammers twice took the lead in the Premier League encounter, initially through Michail Antonio before Lucas Perez fired the home side ahead once more late on after Jamie Vardy had equalised in the second half for Leicester at the London Stadium.
However, late drama ensued as Perez saw a second strike which would have sealed the win for West Ham wrongly disallowed for offside, before Leicester substitute Harvey Barnes bagged a stoppage time equaliser.
"With that goal, the game was finished, but the same as happened against Manchester United, the linesman's decision meant we didn't win this game.
"I have seen the goal and he [Perez] was one metre onside. There is nothing I can do about that. Maybe next season when we have the VAR, it will be fairer and we will get the right result.
"We also conceded two easy goals, including one in the last minute of the game. In most part of the second round, we are conceding two goals in each game, which is too much. We used space in the wrong way in our defending.
"We were pressing too high with our centre backs without any reason and they have good players and put the ball into this space. In general, I think the team played well, but you cannot concede so many goals. We can defend better."