Stoke City moved up to fourth in the Championship with a third win in a row against struggling Peterborough.
Mario Vrancic's deflected shot put the Potters in front after three minutes before Jacob Brown almost made it two after charging down David Cornell's clearance.
Posh did rally with Jorge Grant twice going close before the break but had Cornell to thank for keeping out James Chester's header in the second half.
Sam Surridge's red card in the first minute of added time threatened to give the visitors a route back but their hope was snuffed out when Tyrese Campbell added a second a few minutes later.