By Ewan Murray An incredibly challenging week comes to a close on Sunday for Arsenal as they travel to Manchester City in the Premier League. The Gunners executed the perfect away performance at Tottenham Hotspur last weekend in the north London derby and followed that up with a composed but slightly frustrating goalless draw with Atalanta in their Champions League opener on Thursday. However, facing last season’s Premier League champions, who narrowly pipped them to the title, will be Mikel Arteta’s toughest test. Victory would see them leapfrog the Cityzens in the table, while defeat would c…