Jaques:  Players should be fined their weekly wages for getting involved in incidents like that as well trying to get others sent off 

Jonathan:  Where's Roy Keane when you need him. He would handle costa with ease.  

Seth Gogo Egoeh:  I've never been to a 'Referee School', but even I knew that was a straight red card for Costa. Bad refereeing, bad advert for Premier League. 

Pat Nevin
BBC Radio 5 live

"Zouma is absolutely fantastic in the air, and a great ball in by Fabregas. Zouma has the best leap of any player I have ever seen. But he did not need to leap, there was no-one on him. A good header down and Cech, dropping, still could do nothing.

"Arsenal cannot afford to concede another goal now. At the moment is it total dominance by Chelsea."

I'm not sure where the Arsenal defence was for Chelsea's goal, because Kurt Zouma was all alone, six yards out. Petr Cech got a hand on it but it is asking an awful lot for any keeper to stop it from there.

*The graphic below does not show Arsenal's defence, just Fabregas and Zouma. It was not quite THAT easy!

Image source, Opta

Pat Nevin
BBC Radio 5 live

Image source, Reuters

"I hope the referee doesn't get over-excited here. Ivanovic did not deserve his booking - I'm not sure it was even a foul! Mike Dean needs to calm down a little bit..."

You can listen to live commentary of this fixture via the Live Coverage tab at the top of this page.

Chelsea charge forward from the resulting Arsenal corner but their break ends when Hector Bellerin wins a battle with Diego Costa in front of the travelling Gunners fans, who tell the Chelsea striker exactly what they think of him.

...It is Alexis Sanchez who tries his luck, but his shot hits the wall and bounces wide. Sanchez has had the most shots in the Premier League this season - 29, including blocked efforts - but is yet to score. In fact he has only scored five goals in his last 28 games for the Gunners.

Arsenal's first foray forward sees Branislav Ivanovic shove Alexis Sanchez off the ball on the edge of the Chelsea area. A booking and a free-kick in a dangerous position...

Chelsea start the second half on the attack. Calum Chambers beats Diego Costa to Oscar's cross but the ball bounces into the path of Pedro, who fires wide.

We are back under way at Stamford Bridge.

The Arsenal players - 10 of them - are back out early for the second half. The Gunners are going to make a change, with Calum Chambers on for Francis Coquelin. Chambers will slot in alongside Laurent Kosielny at centre-half.

The Blues edged possession and territory in the first half, will they be able to add to that now Arsenal are down to 10 men? Chelsea have also had eight shots on goal to Arsenal's four. 

Image source, Opta

Pat Nevin
BBC Radio 5 live

"If I was Jose Mourinho, I'd take Costa off right now. I'd put Falcao on, because Costa is not in control of himself. 

"Mike Dean will have eyes for Costa, and any transgression between now and the end of the game and Costa will be off."

You can listen to live commentary of this fixture via the Live Coverage tab at the top of this page.

Pat Nevin
BBC Radio 5 live

Image source, Reuters

"Gabriel knew where Costa was. It was 40 yards from the original incident, but he found Costa and walked back into them. Gabriel will say he didn't know where Costa was, but he did. 

"By the way, the original incident saw Costa put his arm across Koscielny. I tell you what, a few assistant referees would have shouted for a possible red card there as well. 

"It always seems to involve Diego Costa, doesn't it?"

Returning to the red card, replays do not cover Diego Costa in glory. He was involved in three separate clashes with Laurent Koscielny, including a swipe at his face, before Gabriel even arrived on the scene.

Back to the actual football (for now) and good to see Chelsea midfielder Cesc Fabregas being heavily involved in Chelsea's attacks.

Fabregas got more assists than anyone else in the Premier League last season but is yet to manage one so far this season. 

Today, though, he has been more involved in the opposition half (left graphic) than he was against Everton last weekend (right graphic). You can also see below that during the first 20 minutes many of his passes are heading towards Eden Hazard on Chelsea's left wing. 

Image source, Opta