Eddie Nketiah's instinctive tap-in gave Mikel Arteta's men the lead before Joe Willock sealed the points against the 10-man Saints with just minutes remaining on the south coast.
The Gunners were able to really calm the pace of the game down towards the end of the first half, and in doing so, they were comfortable in possession and pushed forward in some promising counter-attacking positions. Once they took the simple route with their passing and allowed Southampton to rush onto them, they created the sort of space that made holding onto the ball a lot easier.
There's no such thing as being calm at the back for Arsenal these days, and as a result, every defensive action or movement in their half was panicked and rushed. They gave the Saints a mandate to dictate the tempo early on in the game and could've easily been punished for that. At times, they were chasing shadows and quite clearly suffered from a lack of confidence in front of goal.
Manager rating out of 10
8 -- Mikel Arteta's decision to drop Matteo Guendouzi showed real leadership -- as did his determination in sticking with the 4-3-3. The Spaniard pushed for Granit Xhaka to be the holding midfielder in a decision that paid off nicely for him, but they could've been home and dry if the boss had instructed them to stop focusing so much of their attention down their weaker left side of the pitch. Alas, his substitutions were timed well, and given their injury problems, this can be viewed as a good day at the office for the former midfielder.
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Emiliano Martinez, 8 -- Aside from a potentially dangerous wayward pass in the 58th minute, this was a really solid performance from the keeper, with the highlight being a dramatic low save from Shane Long in the second half.
DF Hector Bellerin, 5 -- He may be a great "last-ditch" tackler, but this was a poor day at the office for Bellerin. He lost his man far too often, didn't show much motivation in tracking back, struggled with Nathan Redmond's pace and was consistently out of position.
DF Shkodran Mustafi, 6 -- The controversial centre-back wasn't shy about leaving a lot of his defensive responsibilities to his partner, but given his clumsy 11th minute yellow card, he had to be cautious. He does the simple things well, but he's lucky Saints' Danny Ings wasn't at the top of his game.
DF Rob Holding, 7 -- The fan favourite was composed in the air and gets the ball out from under his feet in a timely manner. In this back four, that's more than enough to make a good impression.
DF Kieran Tierney, 7 -- The highly-thought-of defender was calm on the ball at the back and even played a great pass through to Pierre-Emerick Aubameyang, but the fact that he hobbled off in the 70th minute will be a worry.
MF Granit Xhaka, 8 -- He kept the Gunners' play balanced at the back and carried the ball forward with confidence into the Saints' half in a comprehensive performance.
MF Bukayo Saka, 6 -- He went down in pain after a 14th minute challenge, and despite a bright start, he struggled to make much of an impact from that point on.
FW Pierre-Emerick Aubameyang, 5 -- He probably should've scored when rattling the crossbar in the 10th minute, and his decision making was off in the 54th after being put clean through on goal.
FW Eddie Nketiah, 7 -- After pouncing on a lapse in concentration from Southampton, Nketiah proved why he's such a promising striker with a 20th minute goal that set the visitors up perfectly.
FW Nicolas Pepe, 5 -- The electric forward was subbed off in the 63rd minute after an outing that proved why his lack of chemistry with Bellerin will continue to cost Arsenal as the season progresses.
DF Sead Kolasinac, 6 -- He looked nervous on the ball, but he didn't do any substantial damage after being brought on.
MF Joe Willock, 7 -- The youngster was lively upon arrival and reacted well to smash home Arsenal's second goal of the day.
DF Ainsley Maitland-Niles, N/A -- It was a fairly tame cameo for Maitland-Niles, who simply served as a fresh set of legs late in the game.
FW Alexandre Lacazette, N/A -- It was a spirited display from the Frenchman, who set up the crucial second goal after two powerful efforts.