Following today's result, the reigning Champions now have 10 points after five games, the same total we had at this stage previous year.
Cahill was frustrated to only take a point against the Gunners but believes the visitors defended well at Stamford Bridge.
Wenger's Chelsea counterpart Antonio Conte refused to make a direct comment about Luiz's sending off but queried how his side had the habit of never ending with a full complement of players against Arsenal. Alexandre Lacazette was in the right place for the rebound but he could not keep his effort from sailing over the bar.
With neither side able to break the deadlock, both managers opted to bring on the big guns with just under 30 minutes to go.
Luiz, up, until the 87th minute was Chelsea's star man, but under pressure from Alexis Sanchez, lost the ball and lunged out onto the shin of Sead Kolasniac. "I don't know. I would have to see that again on video".
Just like in the curtain-raiser to the season - when Arsenal beat Chelsea in the Community Shield - the west London cub finished with 10 men.
Danny Welbeck is facing yet another lengthy absence from the Arsenal team after limping off in the 73rd minute of their goalless draw against Chelsea with a suspected groin tear.
The Brazilian was given a red card by Michael Oliver for a rash challenge on Sead Kolasinac in the 87th minute of what was an otherwise boring game, but Conte felt that Sanchez had fouled him in the build-up to the tackle. The Blues face Nottingham Forest next in the League Cup at Stamford Bridge on Wednesday night.