Hitting the odd powerful serve isn't the issue. she had to fight through pain to do that and still almost won the match. if anything it shows how strong mentally she is.
What recent examples of stoicism from other players would you have preferred Serena took as a model in these situations?
From this tournament, the only few i can think of are: Nishikori fighting it out against Ferrer despite a nagging knee injury, and Almagro's groin incident, but that isn't a good example as he choked so many times earlier in the match.
Disclaimer: I'm NOT a coach...
Real tennis: https://www.youtube.com/watch?v=yDqnkLJ9BtM