Working with Sarah - timid dog

Aside from Mowgli there was only one dog called Sarah at the dog run.  I spoke to Muriel (names of dog/owner were changed to ensure privacy), the owner who said Sarah was bitten at a different dog run long time ago and had been timid ever since.  She did not ever play with other dogs at the dog run and had only one friend she played with in the park.  I did the Dien Cham protocol on Sarah, and I gave her and Mowgli a treat (Mowgli does not mind if I give other dogs treats especially if he gets one as well; some owners feels it can create fights; I guess it depends on the dogs)  
After a few minutes of trying, Sarah, let me chase her instead of us trying to make her chase us; I guess she did not like the game we suggested - I took that as a good sign.  Mowgli by then was getting more interested in playing with her too and they ultimately chased each other a bit. At first it was only a few seconds before Sarah disappeared behind the bench, but the intervals were getting longer.  This went on for a few minutes.  One could tell how surprised Sarah herself was.  It was a delight to witness the shift.