Arsenal can probably contain United. The defence have trained with Persie, seen him at his best, so they have a good idea about him - the way he moves, his runs and all. Wenger doesn't even need to play Santos today, if he can play Sagna. Play Sagna at right back, Verminator and Koscielny in the middle and Jenkinson at the left. Santos is good at coming forward, but he will probably have a tough time against Valencia, who will make him dance - left, right, centre
Arsenal will probably dominate United in the midfield, and I am expecting United to resort to the same pathetic methods they used against Chelsea in the Capital One match - counter attack, park the bus and more. I don't think Scholes can handle the likes of Cazorla, Wilshere and Arteta at least not alone. Anderson, will most probably struggle too or so I hope.
Now the most interesting aspect of the game, the strikers. Giroud, Podolski, Walcott on one side; Persie, Potato and Valencia on the other. Gervinho was the absolute bomb, but since he's out; Walcott will be the key man. If he starts at the right, he will give Evra nightmares. Evra is pathetic anyway, and Walcott will make him vulnerable as a fish is in no water. Persie will be the threat and Valencia will be looking forward to providing him fabulous opportunities to score. Containing these two players will be the challenge for Arsenal today. Podolski is also a threat and it will be interesting to see if Rafael can handle him - which he probably can't.
Overall, I am looking forward to an exhilarating game today.
My money's on Koscielny to break RVP's leg today and effectively bring RVP's career to a 2 year hiatus.