Have title contenders done enough in transfer window to challenge Arsenal?

Ezri Konsa (right) was Arsenal's last summer signing [Getty Images]Arsenal have started the new Premier League season with two wins as the transfer window closes, looking in ominous shape to retain the crown they won for the first time in 22 years last season.The Gunners had a quiet final day to the window having concluded their business before the traditional late rush – but those hoping to unseat the reigning champions have all been busy expensively re-shaping their squads to mount a cha