The Owls' fight for survival remains in their own hands but will now go down to the final day of the npower Championship season after Grant McCann netted a second-half free-kick.
"There were a lot of nervous people out there on the pitch and it was always going to take something special to win the game," said Jones.
"We didn't do any better or worse than Peterborough did, but they had that one moment that mattered. It was sloppy on our part to concede the free-kick.
"We decided to play a system that has brought us success away this season, but unfortunately that wasn't the case. We had a couple of chances but their keeper saved one and we should have done better with another.
"There are several teams still in danger but our destiny is in our own hands and that is what is important. We're not in the position of having to rely on other results.
"Staying in this league will be a far bigger achievement than winning promotion last season to get here."
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