Replays showed Ramires may have dived to win the spot kick in Arsenal's 2-1 loss, but the Gunners manager admitted his side were not good enough in the opening period
Referee Martin Atkinson pointed to the spot after Wojciech Szczesny challenged Ramires in the area, but replays showed that the Blues midfielder may have deliberately stuck out his leg in order to trip over the goalkeeper.
Frank Lampard’s converted spot kick ultimately proved decisive after Theo Walcott halved the deficit in the second half.
"I don't think it was a clear penalty; I think it was no penalty," he told Sky Sports. "[The referee] could have given Ramires a yellow card.
"I didn't see it well from the bench but I've been told by people have seen it on television that it is no penalty.
"If it's no penalty, it is no penalty, it's either a dive or the player has had to go down not to make contact – I don't know – all I've heard is that it doesn't look like a penalty on television."
Despite his anger at the penalty decision, the Gunners boss admitted his side did not perform well enough in the first half despite being pleased with the way they fought to get back into the game after the break.
"For two consecutive games now we have started not on the front foot," he added. "We come into the game 2-0 down, and [when this keeps happening] it's very worrying.
"Afterwards the team has given a lot but we started on the back foot again today. We were a bit unlucky as well because we did make the first chance.
"We had a great response in the second half. You can see we have quality and spirit but we have to show that for 90 minutes."