The Foxes' title charge has started to stutter after just three wins in the last two months.
Second-placed Posh have narrowed the gap and have the chance to go within four points of Leicester when they meet on Saturday.
Shakespeare said: "I think everyone knows it is more in their interests to win the game than in our interests, but we will be going to give a good account of ourselves.
"I know it is an old cliche, but it is another game for another three points and we will be going there to win. But most of the pressure will be on them."