Goals from Steve MacLean and Paul Heckingbottom gave The Owls the edge against United in a terrible game at Hillsborough but Sturrock will no doubt be demanding improvments on Saturday against Brentford.
He said: "I'm very disappointed because we were absolutely shocking. In the 32 years I've been in the game, that's the poorest game I've seen in my life.
"There were far too many players off form and the only positive is that we've come away with three points."
Meanwhile, David Lucas remains confident despite the error which led to Peterborough's opener and admits he does not take notice of critics who either criticise or praise his form.
He told Footymad: "I wouldn’t know if there was praise or criticism of my performances recently as I don’t take much notice.
"David Moyes at Preston told me a few years ago not to read the papers or anything because if you start doing well it can go to your head and if you believe the bad things which are written then you end up believing them. But as long as you know you are playing well personally that is all what you need."