All the teams chasing Arsenal have got things they need to work on - for Chelsea, their lack of discipline is something that has to change if they are going to challenge for the title.
Moises Caicedo's dismissal in Sunday's 1-1 draw against the Gunners was the fourth time in 13 Premier League games that a Chelsea player has been sent off this season.
One of those red cards, for Malo Gusto against Forest, came so late it did not affect the outcome but against Manchester United, Brighton and now Arsenal, they have been a man down for a significant part of each match.
They have taken only one point from a possible nine in those games, and of course the red card had an impact on each result.
Caicedo was sent off for this challenge on Arsenal's Mikel Merino in the 38th minute, with the score at 0-0. Shearer called it a 'clear red card' on MOTD. Of Chelsea's other red cards in the Premier League this season, Robert Sanchez was sent off in the fifth minute of their 2-1 defeat at Manchester United when the score was 0-0 and Trevoh Chalobah was sent off in the 58th minute against Brighton with the Blues leading 1-0 - they lost 3-1
