Arsene Wenger claimed Raheem Sterling "dives well" after Manchester City benefited from a controversial penalty decision in their 3-1 win over Arsenal.
Gunners boss Wenger also felt the offside flag should have been raised in the build-up to the Premier League leaders' third goal at the Etihad Stadium.
The spot-kick, awarded after Sterling was adjudged to have been bundled over by Nacho Monreal, allowed Sergio Aguero to put City 2-0 ahead early in the second half.
Alexandre Lacazette reduced the deficit but David Silva played in Gabriel Jesus - after both players were ruled onside - to settle the game.
Wenger told the BBC's Match of the Day: "I believe it was no penalty. It was a provoked penalty by Sterling. We know that he dives well - he does that very well.
"And the third goal was offside. I am very upset because at 2-1 we were in the game and looked like we could score. The third goal was the killer.
"It is unfortunate that the game finished the way it finished. I am disappointed. You can accept it if City win in a normal way, they are a good side, but the way it happened is unacceptable.
"It is the second time in two years. We conceded two goals offside last year and we concede a goal here offside again."
Opposite number Pep Guardiola rebuffed Wenger's complaints by referring to the Gunners' contentious win at Burnley last season.
Guardiola said on Sky Sports: "We won in the best way and we deserved by far. The chances we created and the few chances we conceded.
"They tell me it was offside and I don't like to win in that way but sometimes Arsenal win in Burnley, 0-1, 96th minute, with a hand, so sometimes it is like this."
Despite Arsenal's gripes, City were dominant as they extended their club record-winning run to 15 games.
They opened the scoring through Kevin De Bruyne in the 19th minute and created numerous other openings.
With 31 points from a possible 33, Guardiola's men are firm title favourites.
Wenger said: "Can anyone stop them? It will be difficult. The way they have started, the way they are on a run, the quality they have. But you never know. If on top of that at home they have decisions like that, they will be unstoppable.
"I don't want to take anything away from their quality but it happened at a moment when we were really in the game at 2-1 and it killed the game."
Guardiola showed his frustration at times during the game but was full of praise for his side afterwards, particularly given their midweek exploits against Napoli.
He said: "We created a lot of chances and 'almost chances'. Against Arsenal never the game is ended because they are able to change players, they have a lot of quality.
"But considering it was after a Champions League game, they rest all week, we were so, so tired in moments in the game but we were so strong mentally."