It proved to be an excellent decision, with the big Englishman making several fine saves to keep the Jambos at bay.
Then, with eight minutes left, Craig Molloy's shot was parried by Craig Gordon, only for Kean to pop up and slot home the rebound.
The result leaves Saints on ten points after six games, effectively a quarter of the way to ensuring safety. In 2000/01, it took us more than twice as many games to get that total, and we only took one point from six games against the Edinburgh clubs.
We also only managed one away win in the league all season, so we've already doubled that tally!
The win moves Saints back up to fourth, seven points clear of bottom side Motherwell.