Arsenal.com's Nick Teale uses the Bettorlogic form lab to assess this week's Premier League clash.

With leaders Chelsea visiting North London on Sunday, Arsenal have a chance to close the gap at the top of the Premier League.
 
The Gunners are unbeaten at Emirates Stadium this season and have lost just three of their last 15 games at home to 'big four' sides, scoring an average of 1.53 goals per game in those fixtures.
 
Opponents Chelsea have won just one third of games away at 'big four' grounds over the same period.
 
Remarkably, the goals for, goals against and points-per-game averages of the Stamford Bridge side are exactly the same. All three stats bear a 1.27 average.
 
Since summer 2004 Arsenal have done statistically better against 'big four' sides with Manuel Almunia in goal than when he hasn't worn the gloves.
 
With the Spaniard between the sticks, Arsenal have only lost 25 per cent of all 'big four' games, picking up an average of 1.42 points per game compared with 0.95 when he isn't in the team.
 
Finally, the Gunners will be hoping William Gallas is fit to play. Arsenal have never lost at home to a 'big four' side with him in the team.
 
The defender scored a dramatic injury-time equaliser against Manchester United at Emirates Stadium two seasons ago and the Gunners' defensive record is much more favourable with Gallas in the team.
 
When the Frenchman starts at home to 'big four' sides, Arsenal concede an average of just 0.86 goals per game, a 39 per cent improvement on the overall team record over the last five seasons.

Copyright 2014 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 27 Nov 2009