Petra is obviously low on match rhythm, but from the bits I saw of this match on TV Andie was returning serve really well and chasing everything down. She also def. Petra at the AO last year, she must like the feel of her ball. Nice hug.
Petkovic looked reborn, very good match from her, I remember when she played like this against Halep. So possibly a Petkovic QF for Halep would not look easy. If of course, Halep beats Andreescu and all, plus Petkovic also cleans her table.
Petra was just average, a disillusion. And I don't think it's anything about the hand injury, she was good after it and maybe better than before.