Slaven Bilic described referee Robert Madley's decision to award Chelsea a late penalty against West Ham as "unacceptable".
Cesc Fabregas netted from a free-kick and then a hotly-disputed spot-kick at the end of each half as Chelsea battled back twice to draw 2-2 at Stamford Bridge on Saturday.
The penalty, with one minute remaining, came after Michail Antonio challenged substitute Ruben Loftus-Cheek, with Bilic adamant the infringement took place outside of the penalty area.
Bilic told Sky Sports: "We conceded a goal very late which is gutting anyway - no matter how you concede it - but to concede it like that for a penalty outside the box makes it unacceptable.
"It was outside, way outside. It was clear Antonio didn't want to foul him like this. He touched him - I'm not talking about that - but it wasn't even close to the line. It was like one metre [outside].
"We can say 'it is hard, at full speed, the player went down in the box' and everything, but we are not getting those kind of penalties."
Manuel Lanzini and Andy Carroll scored the goals for West Ham, who missed the chance to move into the top four ahead of the match between Manchester City and Manchester United - their two closest rivals for a Champions League spot - on Sunday.
Bilic, though, could not fault his players' effort after they came so close to a first Premier League win at Stamford Bridge in 10 attempts.
"It was a fantastic game for West Ham fans and for me to watch," added the Croatian. "We were better when we led 1-0 but at 2-1 we were also close to scoring a third goal.
"We played fantastic and the game was very good. I think that we did great and we deserved three points from this game because apart from one part of the second half we were the much better team.
"We could have put pressure on Manchester City and a gap on the teams below. We are capable and we are having chances against any team. That approach should take us far."