Goals from Lee Tomlin, Dwight Gayle, George Thorne, Mark Little and Gabriel Zakuani gave the Posh a commanding 5-2 lead with five minutes left, but two late goals from Bolton made the hosts sweat.
Ferguson said: "It was a bit like the old days. We were outstanding for the vast majority of the match, but bang-average in the last few minutes.
"The game should really have been over at 5-2 and we can't afford the make the sort of lapses in concentration that we did late on.
"We are in a battle to stay up and goal difference could be a factor so we cannot afford to give soft goals away, but I don't want to be too critical of my players after producing such a good performance against a team that were in the Premier League this time last year.
"We've worked very hard lately and put everything into the last two games, so I'll give the players Christmas Day off.
"This is the third time we've managed back-to-back wins and now need to kick on and get a third in a massive game at Wolves on Boxing Day."