Or do they? Posh were also written off before pulling off these 10 memorable results in knockout competitions.
We’ve rated them in order of shockability, in reverse order naturally...
1. Colchester 1, Posh 3, FA Cup, third round, 2008.
Colchester were a Championship side and they had Teddy Sheringham in their squad, but Darren Ferguson’s exciting Posh team was starting to take shape in League Two and goals from Aaron Mclean, George Boyd and Charlie Lee secured the win. Sheringham scored the Colchester goal from the penalty spot past Mark Tyler (pictured).
2. West Brom 0, Posh 3, League Cup, first round, 1988.
Fourth Division Posh won this first-leg tie at a Second Division side including Andy Gray and Carlton Palmer before losing the second leg 2-0! Keith Oakes, Nick Cusack and Domenico Genovese (pictured) scored the Posh goals at the Hawthorns.
3. Aston Villa 1, Posh 3, FA Cup third round, 2018.
Villa were challenging for promotion to the Premier League and paid for fielding a weakened side. Posh played superbly to come from behind after conceding a second minute goal. Jack Marriott (pictured celebrating the equaliser) scored twice with Ryan Tafazolli also on target for a side managed by current Posh boss Grant McCann.
4. Posh 1, Leeds United 0, FA Cup fourth round, 1985.
Posh were a ropey Fourth Division side, but still deserved to beat a Leeds team languising in Division Two. Greig Shepherd scored the only goal and Posh hung on to win despite having full-back Martin Pike (pictured) in goal for the final stages.