Air tight argument there...
You could also say had Agger and Enrique not been injured for them, Stoke may not have scored 3.
Injuries happen to all teams, it affects almost every Premier League game. Thats not luck, that's when the quality of a "squad" is truly tested.
If Liverpool lose Suarez next week against Villa, and he's out for a few weeks, it's not luck on our part if we then go and beat them at their place is it?. No, just as it wouldn't be lucky for them if they manage a result and we don't have Barkley.
These things happen in Football. Look at United without Rooney and Van Persie, in the midst of a bad run but nobody with any common sense is labelling it unlucky.