Another yellow for the Blues as Antonio Rudiger brings down Lucas Torreira.

Totting up.

Meanwhile, Emerson can make his way down to the sales on Oxford Street as he is replaced by Jorginho.

What was a game that was bubbling is now like evaporated milk burning the base of your pan.

Dennis Ethan: Arsenal have their tails up early in this match. Chelsea can't keep up with them. Rattled!

Mark Levy: Chelsea played our best football this season with Kova, Jorginho and Mount. Love Kante and he’s our one truly world class player, but were we better when he was out.

Yousuf Ali: Lamps need to take this team back to basics. There's very little organisation. We're disjointed with the ball and awful positioning without it.

Craig Pawson pulls out the second yellow of the match as Mason Mount directs studs to the ankle of Reiss Nelson.

Moments later N'Golo Kante is booked after he hauls down Lucas Torreira.

Celtic's lead is down to two points!

And Rangers have a match in hand!

Reaction here.

Phil McNulty
BBC Sport chief football writer at Emirates Stadium

Chelsea, apart from one moment of danger from Willian and that shot from Mason Mount, just haven't got going. They look a pale shadow of the team that played superbly to win at Spurs.

Arsenal, so far, are dominating.

Alexandre Lacazette whips in a cross from the left but it just eludes the touch of Pierre-Emerick Aubameyang.

The Gunners look comfortable here - Chelsea have yet to introduce themselves.

Calum Chambers hobbles off the pitch to be replaced by Shkodran Mustafi.

BTW that assist was his first since November 2014.

This is vintage Arsenal so far - the good vintage that is.

Alexandre Lacazette hustles his way into the area but stumbles - no need for VAR.

Moments later the Gunners find themselves again in the Chelsea third following a great flowing move, and this time the Frenchman cannot get a shot away.

Meanwhile, defender Calum Chambers is on the deck. Looks like a nasty knee twist.

That was Arsenal's 26th goal of the PL season - 13 have been scored by Pierre-Emerick Aubameyang.

Cripes!

Chris Sutton
Former England striker on BBC Radio 5 Live

A terrific header from Pierre-Emerick Aubameyang! He peels off the back of Emerson and he's not going to miss from that range. A great start for Mikel Arteta and Arsenal.

Phil McNulty
BBC Sport chief football writer at Emirates Stadium

Mike Arteta - very much smart casual - is already making his presence felt in the technical area and he loved that perfect set-piece for Arsenal's goal.

He is directing affairs from the touchline with some vigorous tic-tac and has been throwing his arms up in frustration if Arsenal have allowed the tempo to drop.

Good start back at his old home.

Chris Emeka Ibekwe: I don't see Chelsea winning Arsenal today with the way the are playing.

Darren Christie: See Ozil has been selected again, might As well just field 10 men, will be the same thing. Most overrated player in the league.

Steve Milan: I would prefer Rudi in the middle at the back i trust him more than Zouma.

Mason Mount, who hasn't score for what seems like an age (4 December), smacks a master blaster towards goal which Bernd Leno just about saves.

The winter sun is shining directly into the eyes of the German.

Chelsea with their first attack on goal earn a free-kick on the left edge of the area after Matteo Guendouzi brings down Willian.

The midfielder earns an early yellow.

Flew like a penny floater into the arms of Kepa Arrizabalaga.

The Gunners win another free-kick - fairly central - after Mesut Ozil hits the turf.

Luiz lining up.

Chris Sutton
Former England striker on BBC Radio 5 Live

Arsenal boss MIkel Arteta has been animated in his technical area so far. It will be interesting how Arsenal's players react to him today.