Boro boss Aitor Karanka was a frustrated man after seeing three points slip from his grasp on Saturday.
Islam Slimani’s injury-time penalty rescued a 2-2 draw for Leicester.
For me, it’s a clear foul.
Alvaro Negredo’s double had twice put Boro ahead and looked to have given the visitors a deserved victory, despite Riyad Mahrez equalising from the spot in the first half, before Marten De Roon fouled Wes Morgan in the box and Slimani scored.
Karanka was unhappy with the officials, including referee Lee Mason, after Leicester’s first penalty and revealed Morgan had owned up to fouling Chambers, which forced him to handle.
He said: “I was sure one player pushed Calum Chambers. If I had one doubt, which I didn’t have, the players told me Morgan recognised to them he had pushed Calum.
“I’ve been here for three years and I always say football is about a team. If we want to win or lose we’re working as a team, and the referees work as a team.
“There’s four of them on the pitch and for me it’s difficult to understand how four members of the same team decided for that penalty.
“For me, it’s a clear foul. The fourth official has the same view as me, the linesman has the same view, so for that reason it’s frustrating as football is about teams.”
Negredo’s goalless run since August had sparked criticism, but Karanka always believed the Valencia loanee would end his barren spell.
“I see them every day, work with them every day, he is working a lot and with his quality one day he was going to score,” he said.
“I don’t know if he was aware of criticism, you have to speak with him. When I arrived he was perfect for me.”
Leicester boss Claudio Ranieri insisted the Premier League champions must be prepared for a relegation battle.
The Foxes, who won a shock title by 10 points last season, are two points above the bottom three and, while Ranieri maintains he is unconcerned, Leicester must be aware of their situation.
He said: “For us now it’s important to think we are in the battle of relegation and every point is OK. We wanted to win, but when it’s not possible one point after 93 minutes is OK.
“I’m not worried. But I am a very pragmatic man. Now we are (down) there, last season we were very, very far ahead, but I was always looking behind me.
“We must be patient, see what happens, stay together and let’s pass that moment because sooner or later we will go back.”
Negredo ended an 11-game goal drought with a fine first-half finish before a ruthless strike arrowed beyond Ron-Robert Zieler after the break.
Mahrez’s penalty - after Chambers handled having been pushed by Morgan - levelled, but Leicester were second best for long spells.
Shinji Okazaki hit the bar just minutes before Mahrez’s penalty, but Ranieri conceded his side were poor.
“The performance wasn’t good. They played better than us, I am very happy with our character, to believe until the end something good can happen,” he said.
“We showed fantastic spirit. I and my players knew it was a tough match, they played well and kept a lot of possession, but we created more chances.”
Leicester: Zieler, Simpson, Morgan, Huth, Fuchs, Mahrez (Musa 68), Amartey, King, Albrighton, Okazaki (Gray 76), Vardy (Slimani 65). Subs Not Used: Hernandez, James, Hamer, Schlupp. Booked: Albrighton, Fuchs, Amartey, Vardy. Goals: Mahrez 34 pen, Slimani 90 pen.
Middlesbrough: Valdes, Barragan, Chambers, Gibson, Da Silva, Traore (Stuani 79), de Roon, Clayton, Forshaw, Ramirez (Fischer 88), Negredo. Subs Not Used: Bernardo, Leadbitter, Guzan, Downing, Nsue. Booked: Chambers, Negredo, Valdes, Stuani. Goals: Negredo 13, 72.
Att: 32,058 Ref: Lee Mason