The Gunners entered the half-time interval deservedly ahead of the Red Devils by a score of 2-0.
The hosts were the better of the two sides from the outset, with Nicolas Pepe emphasising that point on eight minutes when his side-footed effort from the middle of the 18 gave the Gunners an early lead.
United laboured in possession, struggling to get past Torreira and Xhaka and open up chances. Their ineffectiveness was further punished from a sloppy corner, when Lacazette was able to muscle in to get a flick-on for Sokratis, who smashed a second past De Gea.
The Red Devils far too infrequently forced the Arsenal goalkeeper into action, as Rashford and Martial were frustrated by a lack of space and service.
A number of shots from outside the 18-yard box was about all the strikers could muster – none of which worried the hosts.
It’s a poor showing from the visitors who stay fifth, while Arteta’s first victory as coach sees Arsenal climb into 10th.