Wenger was livid on the touchline as Juan Mata broke the deadlock moments after Ramires appeared to foul Francis Coquelin.
And his anger increased when Gunners goalkeeper Wojciech Szczesny was adjudged to have brought down Ramires in the box.
Ramires appeared to slip as he tried to twist past the keeper, and Wenger believes the Brazilian should have been booked for diving.
Wenger said: "The referee gave a lot of free-kicks today, and some much less than the Coquelin one. It's frustrating.
"It doesn't mean we should have conceded the goal but, in the big games, these decisions have big implications.
"He could have given Ramires a yellow card as well."
However, Wenger refused to absolve his players from blame for the defeat, the second league game in succession in which they were made to pay for a slow start after last weekend's loss to Manchester City.
"We had a similar start to Man City last week, didn't defend too well and gave them too much incentive," he said.
"We didn't play well in the first half, but we were much more dangerous in the second half, with a different attitude.
"Unfortunately we didn't make enough of our corners, free-kicks and the chances we created. That's why we lost the game.
"It's very damaging for our position in the league and difficult to swallow."