A Grant McCann penalty earned resolute Posh three points at the New York Stadium.Peterborough United held on for three points after a superb defensive display earned maximum points at the New York Stadium against a determined Rotherham United side who failed to take any of their chances in front of goal.
Britt Assombalonga headed a Grant McCann centre over on four minutes after a lively start to proceedings at the New York Stadium.
Ben Pringle, who had earlier fired wide from long-range, curled a set-piece wide of the target on 12 minutes as Rotherham began to impose themselves on the game.
Assombalonga fired over after good work from Barnett on the quarter hour mark. Pringle headed over the bar after a deep Bradley cross on 26 minutes as the Millers pressed for the breakthrough.
Nardiello squandered the clearest opportunity to break the deadlock on 35 minutes as Olejnik could only parry Frecklington's long-range effort into his path, the former Manchester United front man firing over from close-range.
Millsom was next to try his luck for the Millers, but his long-range effort drifted wide of the far post with Olejnik unmoved.
The deadlock was broken by Posh on 51 minutes as Arnason was penalised for handball in the box. McCANN stepped up and coolly sent Shearer the wrong way from the spot to give Posh the lead.
Taylor fired over on 53 minutes after showing great body strength to hold off the defender 30-yards from goal. Revell headed a Pringle free-kick well wide at the other end as the open nature to the second period continued.
Millsom was inches away from a leveller after a forceful run and shot, the left-footed drive going just past the post.
Darren Ferguson introduced former Rotherham loanee Danny Kearns for Swanson moments later. Skarz wasted a glorious opportunity to level the scores at 1-1on 71 minutes, but he side-footed into the side-netting at the back post following Frecklington's deep delivery.
Pringle curled a free-kick wide of the target on 79 minutes after Zakuani was penalised for a foul on Revell. Assombalonga did well to hold off the attentions of two defenders to burst into the box on 87 minutes, but his shot was smothered by Shearer.
Bradley somehow hooked over from close-range after a corner was only half cleared as Rotherham pressed deep into five minutes of injury time.
Final Score: Rotherham United 0-1 Posh
Rotherham: Shearer, Bradley, Arnason, Morgan (c), Skarz (sub Eaves 85min), Agard (sub Tubbs 76min), Frecklington, Milsom, Pringle, Revell, Nardiello. Unused subs: Collin, Brindley, Mills, Tubbs, Tidser, D. Rowe.
Posh: Olejnik, Alcock, Rowe, Zakuani, Bostwick, McCann, Payne, Swanson (sub Kearns 63min), Taylor (sub Newell 76min), Barnett, Assombalonga. Unused subs: Day, Brisley, Ferdinand, Mendez-Laing, Ntlhe.
Referee: Mr Sarginson