Arsenal's frugal transfer window was something of a dissapointment for Gunners fans after the window kicked off in superb style with the signing of Petr Cech from rivals Chelsea, but they could already be looking to January to secure another player.
Spanish newspaper, Sport and German Newspaper, Sport Bild, are reporting that Arsenal and Man City are preparing for a move for the out of favour Real Madrid and Spain international, Isco: http://sportbild.bild.de/fussball/2015/fussball/transfer-news-top-klubs-wollen-isco-demichelis-nach-argentinien-42507104.sport.html
It is also reported that Champions League finalists Juventus are interested in Isco and could make a move for him after Madrid's signing of Kovavic from Inter Milan.
Man City are known to be keen admirers, but after spending big in the summer on Sterling, De Bruyne and Otamendi, they will be concious of financial fair play this season. This could leave the door open for Wenger to make his move, though it is not known how keen Madrid would be to sell yet. The situation will become clearer in January when Rafa Benitez's new side has taken shape.