After a disappointing 2-0 defeat to Bayern Munich in midweek, this was just what the Gunners needed. They faced none of the criticism of recent weeks in a comprehensive win.
Let's look at six things we learned from the rout.
Arsenal's loss to Bayern Munich was not as decisive as it was last year, but the manner in which they capitulated to the reigning Champions of Europe was quite soul-crushing.
During the final minutes of what was about to become a manageable 1-0 defeat, the Gunners switched off for one second against the best team in the world and allowed Thomas Mueller to double Bayern's advantage, making Arsenal's road to the quarterfinals very difficult.
Yet they responded in the best way possible, storming out of the tunnel in front of their home fans and pouncing on a thoroughly lackluster Sunderland side before the visitors could gain any confidence or foothold in the game.
That laid the foundation for the 4-1 scoreline.
After a week-and-a-half of rest, Olivier Giroud truly looked like a man refreshed.
He is still dealing with the revelations of his extramarital transgressions, but the Frenchman, who appeared utterly knackered in his last full match, seemed a man with a purpose.
His second goal involved a touch of luck, but both required excellent finishing skill, confidence and perfect positioning to make possible. Giroud has lacked those critical attributes in recent fixtures, but Arsene Wenger will be compelled to start him in place of Yaya Sanogo in Arsenal's next match.
When I predicted how Arsenal would line up before the match, I omitted Rosicky in favor of Lukas Podolski, assuming that Arsene Wenger would place emphasis on the German's directness and powerful shot while starting the speedy Alex Oxlade-Chamberlain on the right side.
As it turned out, Wenger opted for both Podolski and Rosicky and the result was excellent to watch.
With his seemingly evergreen 33-year-old legs nice and rested, Rosicky sprinted about the pitch as he does when he is on top form and was constantly involved in Arsenal's best attacking moves.
His sumptuous finish after a lovely multi-player tiki-taka move was just the icing on the proverbial cake.
The likelihood of Bacary Sagna penning a contract extension gets smaller with each passing day. That should make Arsenal and the club's fans extremely nervous.
Sagna delivered one of his best performances in one of his most impressive seasons as an Arsenal player. He hardly let a single Sunderland player past him on the right flank and seamlessly slotted into the center of defense and even left-back when asked.
His confidence never wavered and his quality never dipped. Arsenal should bend their standards just once for a truly exceptional and valuable player.
Jack Wilshere is coming into form at precisely the right time. As Arsene Wenger is handing him more opportunities in the center of the pitch, Wilshere is taking them and proving that he can be the box-to-box midfielder Arsenal need.
He was outstanding in linking the defense with the attack, a vital task that Mikel Arteta sometimes has a difficult time doing.
Wilshere was both pugnacious and precise; he got stuck in at the right moments but was an integral part of the Gunners' attacking moves.
His performances this season have not always met the standard he set against Sunderland but if this becomes the norm Wilshere will be a vital cog in all of Arsenal's big matches.
Arsenal leave it late too often for one's sanity against opponents that they should, and almost always do, beat. It was refreshing to see them take charge for once and finish a team off early.
With the scoreline at 3-0 by halftime, it was clear the game was over.
And those were not flukey goals, either. Sunderland were quite tepid, but Arsenal took full advantage and looked like they had set their minds on giving their supporters a well-earned show.
This was not a teeth-grinding, take-the-points-and-run sort of victory. This was Arsenal at their swashbuckling, Wengerian best—and the fans certainly got their money's worth.