Very odd one, Wilshere slipped, took himself out... the ref has to give that as a penalty though it actually somewhat looked like Wilshere might not have caught him, anticipating it and dived or maybe just such a slight contact you can't see it on video. either way when Wilshere goes down like that and the played directly ahead ready to shoot goes, ref has to give penalty I think, looks in real time like a penalty for sure.
It also looks accidental and I think no card at all.
Great ball there from Wilshere, Sanchez should have done better frankly.