A fourth consecutive league defeat for Notts County equals their worst start for 19 years and Peterborough United again denied them a goal as well as a point.
Not only did Notts lose to the only goal of the game for the second home match running but they also lost two of their first choice strikers.
Paul Heffernan was controversially sent off in the 17th minute for what appeared to be use of an arm against Posh defender Sagi Burton - a decision that was furiously criticised afterwards by Notts manager Billy Dearden.
He said he did not believe that it was deliberate on Heffernan's part and that Burton, by over-reacting, had conned the referee.
Posh manager Barry Fry said he did not get a good view of an incident, which reduced County to ten men early in the battle.
Notts later suffered another blow.
This time it was to Mark Stallard, their leading scorer in two of the last three seasons, who went off with what was confirmed afterwards as a broken bone in his right foot. It will keep him out for six weeks.
What turned out to be the match-winning goal arrived six minutes before half time when a Notts attack broke down in midfield with a misplaced use of the ball by Ian Barraclough.
Leon McKenzie gained possession to send Andy Clarke clear and a despairing Steve Mildenhall had no chance of saving his effort.
Before that, Notts should have broken their scoring duck when new boy Clive Platt lobbed tamely into the arms of Mark Tyler and they had two other good second half opportunities.
Darren Caskey, who had come off the bench, should have troubled the goalkeeper and in stoppage time Tony Hackworth was presented with a wonderful chance of rescuing a point.
He went for a spectacular finish, shooting early, and Tyler made an easy save when had Hackworth gone on with a more deliberate finish he must surely have found the net.
For the second game running, the brightest feature for Notts was the performance of 17-year-old Shane McFaul. He came off the bench at Swindon to play well in defence and, on his first starting appearance, was in his more familiar midfield role where he looked thoroughly at home with a really impressive display.