West Ham manager Slaven Bilic said the injury-time penalty that secured Premier League leaders Leicester a point "put a shadow" over a controversial encounter at the King Power Stadium.
Referee Jon Moss had already sent off Leicester goalscorer Jamie Vardy for diving and awarded the Hammers a contentious penalty when he pointed to the spot after minimal contact between Andy Carroll and Jeff Schlupp in the closing seconds.
After a 2-2 draw that leaves the Foxes eight points clear before second-placed Tottenham's game at Stoke on Monday, Bilic said: "We feel frustrated and very disappointed because the game didn't deserve what happened at the end. It puts a shadow over one hell of a football game.
"I'm not eagle-eyed, an ex-referee or Howard Webb. It was hard for the referee. You have 32,000 people here screaming for a penalty for every contact in the box and for every long ball into the box. For a home side it's a penalty or handball and in the other it's a cheat or a dive."
He added: "The game went a bit crazy and they were were losing so it was very hard for him. It is easy to say refs shouldn't be influenced but this is real life - of course it's not a penalty. If you see their penalty you see a dive.
"It was a good game. Goals, penalties, red card, tackles, crosses. We are gutted - we did enough to win the game until the last five seconds."
Of Leicester captain Wes Morgan being penalised for pushing Winston Reid in the area, Bilic said: "That's the way Leicester's centre halves [Morgan and Robert Huth] play and they get away with this all the time.
"Leicester are dangerous from our set pieces. We told our guys before the game but every manager will have said the same thing and they still broke and scored their first goal, so great credit to them."
Foxes boss Claudio Ranieri refused to discuss the referee's performance but praised his players for the manner in which they recovered from conceding goals to Carroll and Aaron Cresswell in the last 10 minutes to get a point.
He said: "It was a tough match. The sending-off changed the match but I am so proud. I always ask my players to give me their soul and their heart until the end and our supporters were also fantastic.
"I never speak about the referee. The referee is part of the game and that's OK for me. I want to speak about my players and we when we conceded the second goal we wanted to draw. It was unbelievable, fantastic, amazing."
Ranieri was relaxed mod about losing two points, despite the fact that leading scorer Vardy will be missing for next weekend's home game against Swansea.
"We are not worried," said Ranieri. "We were worried at the start of the season about reaching 40 points. If a side is better than us then well done because we are doing the maximum.
"Psychologically the last goal is fantastic. It is more important than the point psychologically. It shows we are there."
And on Vardy's absence he said: "Ulloa will come in and he is not just a fantastic man, he is a good striker, a good player."