If the win over Napoli in the Champions League was 10/10 on the Gunners scale, the English Premier League match at the Hawthorns against West Brom was at the opposite end.
However, despite a flat performance from Arsenal, miles away from the highs of Napoli, they still managed to come from behind and manage a 1-1 draw against West Brom, with Jack Wilshere scoring the crucial equaliser after Claudio Yacob had put the home side ahead in the first half.
The draw keeps Arsenal at the top of the table, level on points with Liverpool, on 16, after Tottenham failed to grab their chance following Arsenal's slip up, thumped by West Ham 3-0.
At the Hawthorns, Arsene Wenger brought Jack Wilshere back into his starting lineup at the expense of Tomas Rosicky with Carl Jenkinson coming in at right-back for the injured Bacary Sagna.
However, this Arsenal team that came out was not the classy, untouchable XI that wooed and oohed Napoli on Tuesday at the Emirates.
The Gunners barely got out of the blocks in the first half, with West Brom also not exactly threatening too much.
In fact the first 40 minutes or so was not too dissimilar from the Capital One Cup third round match that the two sides played a little over a week ago.
For Arsenal, Aaron Ramsey and Mesut Ozil were not their influential selves, while Jack Wilshere was also struggling to put his stamp into the game.
The referee did not really help matters, and was having a bit of a nightmare in the first 45, blowing his whistle for soft fouls and turning a blind eye for the obvious ones, much to the chagrin of both sides.
Neither team were playing in their top gear, and it looked like the first half would end goalless, only for West Brom to strike late.
A corner was cleared out of the box by Carl Jenkinson, before the ball came back to the initial corner-taker Morgan Amalfitano down the right. The West Brom midfielder took his time before measuring a pinpoint cross for Yacob to head in at the near post, past the despairing dive of Wojciech Szczesny.
That meant a 1-0 scoreline at halftime, and the first time Arsenal have conceded a goal for the first time in a game this season.
Nicolas Anelka, the man who made his name at Arsenal as a teenager, had the perfect opportunity to make it 2-0 early in the second half, but couldn't sort his feet out in time with the goal gaping after some good work from Saido Berahino.
Arsenal were still not at their best, not even remotely, but the longer it stayed 1-0 the more the chances, you knew, of Arsenal getting back in it.
And after a couple of forays, that is exactly what happened. Giroud held the ball up really well before playing in Rosicky, who came in for Ramsey in the second half. The midfielder laid the ball off perfectly for Wilshere, who struck a sweet half-volley, which took a slight deflection on its way into the back of the net in the 63rd minute.
Arsenal, buoyed by the goal, looked for the winner and the game opened up considerably with both sides looking dangerous on the counter-attack.
However, try as they may neither side could find that important goal, as Arsenal settled for their first draw on the Premier League campaign.
At White Hart Lane, Tottenham had an absolute nightmare, as West Ham ran riot in the London Derby. The Hammers found three goals past Spurs, a team, before today, had conceded only two goals in the Premier League.
Winston Reid got things going in the 66th minute, before Ricardo Vaz Te and Ravel Morrison added to Tottenham's misery. The result sees Spurs all the way down at sixth, when a win could have possibly taken them to the top.