2. Vigilance during Set Pieces
United will try and mount many challenges during set pieces, especially corner kicks where players like Fellaini and Smalling will dominate physically. Koscielny and Mertesacker work wonders together, but sometimes can be horribly out of position. Ballerina and Monreal will match United wingers for peace and should be careful when they go into challenges on the flanks. United has capitalized more than once from a good Juan Mata delivery, which is met by Fellaini in the swamp of bodies in the box. Wenger has to be wary of letting that happen.