Of course credit for Walcott's run and the ability to cross (did well overall), but a perfect ball wouldn't have put Welbeck into the position to intuitively deliver the the ball across the goal line the way he did with his presence of mind, a moment of magic. Or maybe a goal could only happen this way
Class player? Far from it. This is the best way to use Walcott, as impact sub to use his pace against tiring defenders. He is such a frustrating player to watch when he starts (apart from few games), he is still young enough and can go on to become very good player but he is far from class player. He is just a speed merchant.
Also it was not perfect ball, it was Welbeck's presence of mind to pull that off, not many would have gone for that option.
Still massive credit to Walcott though, he changed the game completely and deserved Man of the match.