Stephen Crainey saw red as Fleetwood Town slipped to a third consecutive defeat on a the road - a single goal the decider against Peterborough.
Fleetwood have been made to pay in recent weeks for a failure to take advantage of their domination.
It was a story which continued at London Road.
Graham Alexander’s men dominated the opening 45 minutes but found themselves behind on the stroke of half time.
It was an error from the normally reliable Stephen Jordan which allowed the home side to nose ahead.
A long punt should have been bread and butter for the experienced defender to deal with, Jordan fluffing his header, Conor Washington snapping up the loose ball and rolling it past a stranded Chris Maxwell.
Just 30 seconds before Town should have taken the lead for themselves, Gareth Evans keeping the ball in play and spinning the ball into the Posh box.
Jamie Proctor couldn’t connect with his head but Stephen Dobbie was at the back past to send a volley into the side netting.
It was the second good chance for Dobbie who earlier had found himself one-on-one with Peterborough keeper Ben Alnwick but unable to lift it past the former Blackpool target.
Josh Morris also went close, drilling a shot from 15 yards, Michael Smith’s crucial block on the line denying Fleetwood an opener.
The second half was one of deep frustration for Fleetwood who couldn’t match the creativity they showed before the break.
Peterborough were content to play posession football, thretening the visitors on the break and looking, wherever possible to run the clock down.
Josh Morris forced a save from Alnwick from a set piece but chances were few and far between.
And Town’s fate was all but guaranteed ten minutes from time when Stephen Crainey was judged to have felled Marcus Maddison.
A second yellow saw the Fleetwood full back sent for an early shower, Peterborough using the remaining minutes to push for a second.