Well, it's been a week, hasn't it? Full of sort-of optimism heading into Arsenal's Champions League showdown with Barcelona, that optimism collapsed faster than Lionel Messi after a Flamini tackle, and here we are, facing yet another Round of 16 exit from that competition. So, I can see why you'd be a little down, feeling a little skeptical right now.
But don't! This is a great chance to focus on the Premier League, where Arsenal sit two points behind Leicester City and level on points with Spurs. Both Leicester and Spurs are playing relegation candidates - Norwich and Swansea, respectively - so it can probably be assumed those results won't go Arsenal's way, because the world is a cruel hideous master who cares not. All of which makes this the latest in a string of Massive, Massive Games for Arsenal.
Arsenal come into this game not quite unscathed - in addition to the usual, Alex Oxlade-Chamberlain has joined the long-term absentee club, out for seven weeks with knee problems. Anthony Martial may well be rested for United, after suffering a small hamstring issue (not an issue of a small hamstring, but...oh forget it) in their midweek win against Meat Land. David de Gea and Chris Smalling are also facing late fitness tests but may feature. United are, however, short several players, actually, with Fellaini, Rooney, Schweinsteiger, Luke Shaw, and Ashley Young all out.
This game and this rivalry may lack the bite it had in the late 90's and early 00's, but this is still a big game, and a game Arsenal need to win. They beat United at Old Trafford last year in the Cup; now it's time to do it in the league.