The reaction from Robin Van Persie as the fourth official held up his electronic board to reveal that Arsene Wenger was removing the impressive Alex Oxade-Chamberlain for a somewhat disinterested Andrei Arshavin was somewhat reminiscent of Steven Gerrard’s when Rafa Benitez decided to drag Fernando Torres in a must-win fixture against Birmingham in 2010.

Torres’ replacement, David N’Gog, would go onto miss a host of chances, arguably costing Liverpool two precious point. At the conclusion of that season, Liverpool missed out on Champions League qualification, and Rafael Benitez would face the axe. Wenger’s mistake may prove just as pivotal as Rafa’s did, and one wonders whether or not a similar fate awaits the long serving Arsenal manager.

Arsene defended himself against the immediate criticism from the fans, and the disbelief from his own player, claiming that he need not answer anyone who questions his management of his team:

“I have to stand up for my decisions and I do. I am 30 years in this job and have made 50,000 substitutions and I don’t have to justify all of them.”

Not all of them, Wenger, but when you take off arguably the best player on the pitch to that point, and replace him with a player who offers half the energy and impetus, and little defensive cover, then perhaps you ought to have some form of justification. Factor in Arshavin’s complacency in possession and the shambolic defending which allowed Valencia to break into the box with ease on the way to United’s winning goal, and leave Arsenal even further behind in the race for Champions League qualification, and you can begin to understand the desire from the Arsenal support for a reasoned explanation.

Wenger is not one to break under the demands of others though and his dedication to his philosophies and style has at times served him well, but it appears his stubbornness could be his undoing. Wenger only had to look across to his opponent’s dug out on Sunday evening to see that even the oldest of dog’s need to learn new tricks to stay in the game, and unless Wenger can change his approach to meet the demands of a gruelling and unforgiving Premier League campaign, Arsenal will not end their trophy drought any time soon.

Wenger’s refusal to bridge the obvious gaps in his squad in the transfer market has once again left his side wanting against their closest competitors. Injuries have not helped Arsenal’s cause, but they are hardly an excuse either, as teams around them continue to deliver results without key men at key times, and now sitting five points behind fourth placed Chelsea, Arsenal will know that they have their work cut out for them if they are going to retrieve this season and qualify for the Champions League.

The predicament in January for Wenger is made worse by the fact that January is no time to amend the issues that currently afflict his Arsenal side. Signing anyone now would most likely be a case of too little, too late, particularly with a number of players coming back from injury, and in all likeliness would be able to change little, with less than half the season to play.

Champions League qualification remains a distinct possibility, particularly with Chelsea floundering as they are, but it is the regression in goals that will concern Arsenal fans the most. From title contenders to whom qualification for the biggest club competition in the world was a mere afterthought, to battling just to qualify is a concerning drop for a club of Arsenal’s stature, and it is up to Wenger to realize that things have to change at the Emirates if Arsenal are going to harbour serious hopes of maintaining their status as one of the England’s Champions League regulars.