Middlesbrough left it late to overcome struggling Peterborough as Paddy McNair and Josh Coburn netted to settle an otherwise unremarkable Championship game.
Northern Ireland international McNair had his shirt pulled in the box with five minutes to go, prompting referee John Busby to point to the spot, and keeper David Cornell was sent the wrong way.
Substitute Coburn added a second in injury time, connecting with Martin Payero's centre to condemn Posh to a sixth straight away defeat.
The Teessiders had the better of the game up to their final five-minutes flurry but looked as though they would have to share the spoils.