arsenal face table-topping chelsea at the emirates stadium on sunday .
cesc fabregas returns to the emirates with chelsea for the first time .
arsene wenger says his record against jose mourinho will have no impact .
alex oxlade-chamberlain and mikel arteta are set to miss out on the game .
per mertesacker is ' 50-50 ' for the game having not trained at all .
read : ` proud ' alexis sanchez targets ` many titles ' with arsenal .