The player who attracted the most discussion among Arsenal fans was Brazilian left-back, who we highlighted before the game as a weak link, up against arguably the league's best right-winger in Antonio Valencia.
But it wasn't just Santos' shaky performance on the pitch which got Gooners raging. It was his decision to swap shirts with Robin van Persie at half-time.
The Manchester United striker had already put the home side 1-0 up when the half-time whistle blew, and when Santos made the decision to ask for the shirt of a man considered a 'traitor' by the majority of the Arsenal support, fans found it baffling.
Bafflement quickly turned to anger, with thousands of supporters venting their frustration on Twitter, furious at a 'lack of respect' shown to the Gunners badge, halfway through the game.
As the outcry and abuse became difficult to ignore, Santos' wife spoke out on the social networking site to defend her man.
Here is what she had to say...
The english should understand better the Brazilian culture before judging someone...no one stops being friends just for changing company...— Suélem L. dos Santos (@Suelem_Leal) November 4, 2012
What do you think of her defence? Any better than his defending?!
image: © Ronnie Macdonald