In my native language they say:
A L' E' INUTIL INSEGNA' AL MUS, SI PIART TIMP E IN PLUI SI INFASTIDIS LA BESTIE!!
(translated) There is no gain in teaching the donkey, you waste your time and annoy the beast
Sofia is dangerous not only because she's on her beloved North American indoor hardcourt, but because she's recently snapped a 5 match losing streak and is no doubt playing with new found confidence. Heather will have to be on top form.