Newcastle manager Alan Pardew was quick to defend Joey Barton after seeing his side pull off an astonishing fightback from four goals down to draw 4-4 at St Jsames' Park.
The Gunners wasted an opportunity to pile pressure on Barclays Premier League leaders Manchester United, despite going 3-0 up at St James' Park within 10 minutes and scoring a fourth 16 minutes later.
However, after midfielder Abou Diaby had been sent off three minutes after the restart for pushing Barton to the ground following a rugged challenge, they crumbled and shipped four goals inside 19 bewildering minutes, the last of them Cheik Tiote's stunning 87th-minute equaliser.
Wenger, who was also critical of the two penalties awarded by referee Phil Dowd, said: "It was a completely unnecessary sending-off, and I believe Barton was very lucky to stay on the pitch for the tackle on Diaby."
But Pardew said: "You have got to make a challenge. It was a proper, honest challenge - I have seen it two or three times and there's nothing wrong with it.
"He goes for the ball, he wins the ball clean. He is aggressive in the challenge, he takes a little bit of the player after he has won the ball."