Arsenal's season is still in its infancy but already the Gunners find themselves under huge pressure as Arsene Wenger takes his side to Istanbul for a crunch Champions League qualifier against Besiktas.Qualification for the group stage of the competition is crucial, both in terms of success on the pitch and in financial terms - some would argue the two are mutually exclusive - and Wenger himself has admitted his "desperation" to get through.He won't be helped by something of a defensive crisis in the Arsenal ranks, although he has reinforcements to call on in Istanbul, and the Gunners have a tough job on their hands to secure a decent result to take back to London for next week's second leg.TEAM NEWSBesiktas have concerns over midfielder Atiba Hutchinson, who has a hamstring problem and is rated as only 50-50. Former Chelsea striker Demba Ba, who scored a hat-trick in the second leg of the third-round tie against Feyenoord, is expected to lead the line for the Turkish side.Arsenal manager Arsene Wenger is considering bringing defender Per Mertesacker back from his post-World Cup layoff early as injury cover. Defenders Laurent Koscielny and Kieran Gibbs suffered knocks in Saturday's last-gasp 2-1 win over Crystal Palace meaning Mertesacker, who last week announced his international retirement, could be drafted in to play in Turkey.MANAGER QUOTESSlaven Bilic: "Arsenal are the favourites, but we also try our best. We have a dream and we will do our best to make it happen. We are ready with everything for this game. We know very well the opponent and have prepared well. We have respect for our opponents, because we are playing against one of the strongest teams in Europe. We have a game plan, and the players have to implement this plan."Arsene Wenger: "We are desperate to go through, no matter what it costs we want to go through. We have always a difficult draw, we had Fenerbahce last year, this time we have Besiktas. It's difficult. It is a big test. We had a short preparation, and we know that in one week we have three big games. Besiktas home and away, and Everton in between. Every game you win makes you stronger. On that front winning games helps you to gain confidence. The group still needs to grow."(uk.eurosport.yahoo.com)Bakudaily.Az