Roberto Martinez said he felt Everton were hard done by in Saturday's 3-1 defeat at Manchester City.
The Spaniard was disappointed with a number of decisions and left particularly incensed by the award of a second-half penalty against Seamus Coleman.
Everton had taken an early lead at the Etihad Stadium through Romelu Lukaku but the hosts hit back through an Alvaro Negredo strike and a brace from Sergio Aguero.
"If that's a penalty, it's an impossible game," said Martinez when asked to reflect on Coleman's supposed foul on Pablo Zabaleta. "There's contact but no impeding. It's harsh and that should never be a penalty. There wasn't even the consistency to give the penalty on Lukaku from [Matija] Nastasic in [another incident] in the first half.
"It was a shame because I thought it could have been a fantastic game of football."
The Blues raced into a 15th-minute lead when the red-hot Lukaku bagged his fourth goal in three league games, showing skill, pace and power to find a way past Joe Hart.
But Negredo's immediate response was followed by an Aguero double - the second of which being the controversial spot-kick.
And despite being frustrated by the decision, Martinez admits his side could have done more to extend their unbeaten run in the league.
He said: "We had a good start but unfortunately we conceded three goals cheaply and that makes it very difficult to get a positive result at the Etihad.
"I thought we began brightly. We wanted to score the first goal, but couldn't keep our lead long enough. Those five to 10 minutes after scoring are important.
"It was a blow because I saw it as an open game, a fascinating game."