Unai Emery is hoping Aaron Ramsey is fit to start against Napoli – but faces major fitness doubts over two other key players.   Gunners boss Emery is sweating on the fitness of Laurent Koscielny and Granit Xhaka who both missed Sunday’s defeat at Everton .  Ramsey was on the bench at Goodison Park but the hope is he will be fit to face the Italians in the Europa League on Thursday night.   Xhaka has returned to training but Koscielny is still troubled by a foot injury with Arsenal desperate to make the most of home advantage on Thursday.  Emery said: “We were waiting to see if Laurent could play but it wasn’t possible. I want to be positive for Thursday, it depends how he is progressing.  “Xhaka is the same. They are going to be doubts for Thursday.  “But we have players and can take the performance with all the players.”  Arsenal were well below-par as they were beaten 1-0 by Everton on Sunday, a defeat that dented their top four chances.  While the Gunners’ away form has been poor, they have been excellent at the Emirates and Emery will hope that continues against Napoli.  Arsenal have won their last seven home matches in all competitions and will look to build a first leg lead to take to Naples.  The Serie A side are without Amadou Diawara and Raul Albiol, leaving Carlo Ancelotti short of options in central defence.  But Lorenzo Insigne and Faouzi Ghoulam made their returns from injury in the draw with Genoa and are in line to feature.  Alex Meret is likely to start in goal with Arsenal loanee David Ospina yet to return from a head injury.